Trying out clothes that doesn't fit, oiling the belly, sucking the belly in and pushing it out again, light patting/slapping, rubbing

Anal sex if their into that! I always loved seeing the rare sight of a pregnant girl having anal with her belly nice and big.
Interracial sex is also a bit thing for me as well.

other then that, maybe cosplay as characters from anime, comics, tv shows, or even people's stories that they write, as well as pregnant girls doing role play (schoolgirls please!)