Reynolds and Alma have a complex kink / bdsm relationship, without a clear division between dominant and submissive roles.

Reynolds’s profession and life are about a type of subjugation of the feminine; through his work he decides what feminine beauty is, and then he molds women to fit this image (literally, eg the line when he is measuring Alma and he says that through dressing her he decides whether she has breasts or not). 

Alma sees this immediately (and Reynolds seeing her seeing him is the spark of their relationship), and in their very first interaction she begins to create the dynamic of their relationship: he makes a preposterously specific order, positioning himself as master whose arbitrary whims she as servant must fulfill, which she agrees to, but she also works to undermine his authority through a soft (and private) humiliation of infantilizing him and recasting his strength as a type of weakness (an ostensibly wealthy man of refined taste becomes “the hungry boy”).

She generally works to reverse the power imbalance of her role as servant, and uses it to force Reynolds into a weak position he cannot achieve on his own, and then when he is weak, nursing him to strength again – a kind of extreme, enforced submission and dominance through care, a position of weakness and submission to the feminine which Reynolds desires but is unable to actualize of his own accord. Part of what allows Alma to fulfill this role for Reynolds is that she deploys her power totally through feminized activities, so that Reynolds submits to the feminine and not to a woman deploying masculinized power (like his sister Cyril). If we like to talk about the Madonna and the Whore, then Alma is, in the parlance of our times, both Mommy and Brat: Brat because she works from below to undermine Reynolds’s authority over those he views as under his control, and Mommy because once she has completed this project of subversion, she takes on her own authoritarial role as a caregiver who determines all aspects of Reynolds’s experience during the period of his weakness/submission to her.

There is more here about the ways in which Reynolds exercises a complicated mixture of masculinized (he decides how women should be) and feminized power (he does it through dressing them up), and of course a key element is also that he exercises dominance over the feminine by literally serving powerful women. Consider that Reynolds’s relationship to his clients reflects Alma’s relationship to him: control via service which creates a network of dominance and submission which turns back in on itself.

Symbolically, Reynolds’s and Alma’s relationship articulates ways in which masculine and feminine roles can exercise power over each other in intimate relationships (not with universal consistency or equality, but Reynolds and Alma settle into a dynamic where they each dominate and submit to each other in intertwined ways which are gratifying for them – although if forced to I’d say Reynolds is more clearly the sub in this relationship, as traditionally defined).

Additionally, there is an incestuous undertone in Reynold’s relationship with his sister Cyril, who previous to Alma served some of the same functions as her for Reynolds, namely the structuring of the household, position as a confidante, and of course most importantly, the person who decides what and how he eats when he’s at home – a person nominally in charge of him. Reynolds allows Cyril a certain amount of this intimacy but for a variety of reasons, the aformentioned masculinzation of Cyril’s power and position, and also perhaps because of incest, Reynolds cannot fully submit to her and she cannot properly dominate him. Alma can dominate Reynolds because she is exterior to his basic identity and because she can force him to submit without his having to grant her permission to do it. 

Class is also an aspect of this relationship, and Alma being of a lower class than Reynolds both facilitates and heightens their power exchanges.

See also their names:

Alma, from the latin Almus for “nourishing” – the double-entendre here in that she both literally nourishes Reynolds by serving him food, and nourishes him sexually / spiritually through the way she deploys physical nourishment.

Cyril, Reynold’s sister with a masculine name, from the Greek “lord and master”, and she is the lord of the household initially, but this relationship cannot fully be consummated at least in part because Reynolds wants to submit to femininized care and not masculinized control. Cyril, for her part, is perhaps the character in the most masculinized role and while she likes the power Reynolds has granted her, she also seems to resent (rather than encourage, like Alma does), his weaknesses and the aspects of feminized power that he inhabits – in other words, Cyril sees Reynolds’s weakness and wants him to be strong, but Reynolds wants a woman who can allow him to be weak.

and Reynolds too from Germanic roots which mean more or less “the power to decide”.

PTA has been exploring these types of complicated submissive / dominant relationships for a while, often without clear distinctions between those positions (which reflects the says ) and without necessarily being sexual even if they are sexualized (which is where I draw the connection to Cronenberg, where sexuality is not necessarily about or focused on sex itself). He also uses them to complicate categories of feminine and masculine and to articulate reciprocally shifting power imbalances. These things are of course aspects of , and PTA seems to be interested less in the play itself than the ancilliary ways in which people negotiate these aspects of their relationship dynamics within a broader context of their shared lives. 

I see these kinds of relationships as existing between Daniel and Eli in There Will Be Blood, between Lancaster, Freddie, and Peggy in The Master, between Alana and Gary in Licorice Pizza in a more juvenile or less developed form (they are constantly feeling out which one of them is supposed to be in charge in which situation, often both enjoying and being exasperated by their inability to achieve clarity here – contrast with PTA’s adult characters for whom this kind of clarity is often dangerous and fluid negotiation is more interesting/exciting/vital), in Magnolia in the figure of Frank TJ Mackie, but see also the simultaneous power/responsibility of care position that Philip Seymour Hoffman inhabits, Willima H Macy’s quest for body modification to correct what he sees as a deficiency which prevents him from accessing power (but of course his character’s insistence on what he needs to be done to himself is so overdetermined that we must question where he really desires the solution he invented or if he invented the solution because he desired the position it allows him to inhabit – he insists that he must have someone else fix him in order for him to be loved and to love himself – see streams here which exist also in Reynolds in Phantom Thread and Freddie in the Master, etc). and between the entire network of the ensemble within Boogie Nights. (I’m sure this exists in Punch-Drunk Love also but it’s been forever since I’ve seen it so I can’t speak specifically, and I’ve not seen Inherent Vice or Heard Eight.)

These are all about negotiating power within different types of intimate relationships – sometimes they are about acknowledging intimacy in relationships which we like to pretend aren’t intimate – and for PTA the power of intimacy seems indivisible from articulations of sexuality and gender identity (indeed, one might say that a theme here is about how sexuality and gender are themselves determined by constantly renegotiated power within intimate and social relationships), even if, again, they are not necessarily focused on sex itself per se, or not any form of typical sex, anyway.