>>2844154Unless your understanding of a sex face is limited to dumb ahegaos, you should see Ademar's Izumi, he has created several dozen morphs just for that purpose, which nobody else uses. (And they're practically exclusively used in his paid stuff.) I've been thinking of sharing my facials conversion pack, but what I currently have also uses unique morphs sometimes, and I don't yet feel like going through it and reworking it again. More busy with adapting all the loops first to make them instantly reusable, in addition to other projects.
Other ideas include: blowjob faces and associated separate morphs (bulging cheeks—individually, sunken cheeks—both, lip extension, mouth wide open), Biting lower lip (lower jaw moves backward), Biting upper lip (lower jaw moves forward), various common tongue morphs, and morphs that reshape eyes.
Might as well add the jaw control and lip weights while you're at it. Weighing is highly dependent on the detalization of the face, and IK control limits are also affected by it. Weights absolutely must be very smooth but also very even in the front, so the fewer polygons the face has, the lower your weight ceiling and lower the negative X limit of jaw control. Mine uses -80/5 X limits with a weight ceiling of 50 (compared to Izumi's -35/0 and 100).