working with sex and gender (plus "tantra"):
[See also the section: extremity replay and creativity: panic, trauma, sexual arousal]
[See also the section: "subtle energy" and "energy work" and mental models]
Similar to the discussion on breathing, in section "breath," the muscular/glandular components of sexual arousal, orgasm, ejaculation, etc., have a volitional skeletal muscle component and (indirectly affectable) autogenic components.
A lifetime of action and intent (as well as improper use of breathing, attentional, "energy," and "tantric" practices) can layer and "convolve" volitional components with autogenic responses.
Eventually, as part of meditative practice, some people will want to work directly with sexual arousal. It’s a little bit different than working with breathing. Breathing is always available and somewhat gets deconvolved well mixed in with everything else. Because sexual arousal, tumesence, detumesence, is more of a state that is (fuzzily) entered and exited, there’s maybe a possibility of being a bit more deliberate and planful.
(There will of course always be creative interplay/synergy between volitional [and/or effortless/spontaneous] skeletal muscle and autogenic skeletal and smooth muscle responses, and everything else. Engagement with practices/protocols can sort of unlayer and refactor so that it’s the "right," unlayered, spontaneous, dynamic, sensitive, responsive amount [which of course also whatever it happens to be at any particular time].)
So, for any sexual phenotype, male, female, etc., this can look like slow, patient, intermittent light touch, and sort of letting that reverberate. If you’re experienced with main practice p2, you may sort of quickly get sense of how to approach this. You might, say, observe how any of your diaphragm, chest, core, perineum, glutes, etc., involuntarily contract upon touch, and how, little by little, that can be disentangled, refactored, perhaps reduced or perhaps just changed in good ways. And this will alter one’s experience of intensity and pleasure.
(Of course, "practice" should "eat itself" over time until it’s no longer needed, until there’s "just sex," or anything.)
Just as with one’s breathing, and of course anything and everything, mind and body, because of occlusive/compensatory layering, some things won’t change until lots of other things change, many of those things maybe seemingly "far away from sexuality," or not.
As with meditation proper, it can be good to explore different postures—sitting, kneeling, standing, laying down, because the muscle engagement profile will be so different. You can of course explore things with and without sexual partners. Another thing to vary is exploring with and without orgasm or ejaculation. I think it’s generally fine to never withold orgasm, if abstaining doesn’t feel right.
(This whole section mostly refers equally to men and women. With respect to semen retention practices that involve strong muscle contractions, I’m personally not a big fan, in part because they can cause damage or at least irritate internal, tissue and sphincters, even when timed correctly, and in part because they can potential facilitate layering that can work against global detangling. If you’re interested in such practices, it might be good to wait to explore until you have a good "p2 sense" through lots of detangling and delayering, but also experimenting sooner rather than later can be good in general.)
Finally, working with sexual arousal is especially an opportunity to explore, expand, disentangle, and "find your way back" to gender and sexuality that could be occluded, layered, or tangled, e.g., bottom, top, submissive, dominant, masculine, feminine embodiment/energy/stances/etc. (((((((This includes all of gender, presentation, orientation, "cultural role/orientation," "career role/orientation," "intimate relationship/romantic role//orientation role/orientation," "social role/orientation," "sexual role/orientation," having kids or not, attachment and pairbonding styles, monogamy / nonmonogamy / etc. style, kinks / fetishes / paraphilias, not to discretize or reify any of these things and / but they can go as deep as one's entire life and affect all of it, all the way through. There's a whole section waiting to be written about this parenthetical. In brief, people can have layers and layers of cultural stuff, "shoulds," stuff from other people, shot through with "developmental hardware things" bubblng and filtering up, all the way from the bottom, as it were, as well as multiple "whole system twists" around all of that. And, as part of meditation or anything, one can untangle, disentangle, metabolize, integrate all of that down to something like the "bare metal" which will always have situated, contextual, nebulous expression albeit perhaps a clearer and clearer set of patterns shimmering and shining through. As part of that one sort of refactors the nebulous "story of their life" (which is or perhaps becomes largely implicit, drawn upon in new ways, as needed) as all of this can run through all of that [sic], including other things like health, childhood experiences, notable and traumatic events, energy metabolism, revelatory social or cultural or private experiences, all of it, all mixed together, to perhaps be cognitively and experientially and behaviorally clarified (not to reify that or hold that up as a goal as such). For nonnormativity, one might find a patch or patches or dappledness or splash pattern of "chimerism" or "mosaicism" (to borrow those words) of "neurological genderedness," for which perhaps different parts of the brain hormonally or developmentally did or didn't first-pass reach some potential counterfactal-non-existent-god's-eye-view genetic or chromosomal or hormonal or endocrinologic(sp?) expression, perhaps, perhaps, as then experienced from the inside. And the meditative work is sort of, over time, unwhirling and unwhorling all those layers and twists and resting in all of that, as all that, luminously all that, just as it is, as nebulous and contextual part and parcel harmonized with living and life and choices and relationships, and the possible unfair choices and opportunities and privileges and disprivileges and surprises and insights and sorrows and regrets and joys that that comes with.)))))))) For some people this will incidental, especially though not necessarily when things are pretty normative, and for some people this will be critical.
For all of this, allow for breathing, movement, vocalization, and so on.