M/F; like it says on the tin, Peter getting fucked by a woman with a strap-on.

OTA; forced personality and sex drive changes brought about through brainwashing, technology, magic, or biological agents (sex parasites? symbiotes?).

OTA; sex in front of an audience or in a group setting. Good with night clubs, orgies, or any other scenario that can make it work.

M/F; Peter being kept prisoner or as part of the sluttification kink and being used to breed.

OTA; stimulation and/or sex that's brought about through telepathic means. Up for doing an AU or incident where Peter develops telepathic powers (technopathy could also be worked into this, since he used to have those abilities).

OTA; Sex as a civil/religious/magical ceremony, with some specific purpose to it.

OTA; An AU that plays around with the fact that the Spartoi (the species Peter's dad belongs to) used to belong to the same species as the Shi'ar (who descend from bird-like creatures). He'd go into rut, strut around for his potential partner, and get very domestic. The knotting's just tossed in as a bonus.

OTA; I have an AU written out over here where Peter leads an invasion of the Earth. He wouldn't exactly have a harem in this setting but we can use political intrigue as a background for sexual scenarios.

OTA; an AU where Peter (and your character, if you'd like) find the Black Vortex, accept its power, and become space gods, mad (maybe, and horny) with power. This could be mixed with any of the above.