Probably fleshlights being used inside pussies, if only because that's actually common enough to have at least a minimal amount of content available. It basically objectifies both man and woman while also subjugating them as not enough for one another.

https://sexblogging.com/vagception-inserting-a-fleshlight-sleeve-into-my-vagina/
https://coomer.su/onlyfans/user/starryfawnn/post/800891650
https://www.xvideos.com/video77744257/how_to_make_her_pussy_tight_again
https://pornhub.com/view_video.php?viewkey=ph6391c649078b9
https://pornhub.com/view_video.php?viewkey=ph63bb016e87bff
https://www.xvideos.com/video77743879/stepsister_rides_his_male_mastrubator_while_his_dick_inside

There's also female condoms being used, but the only full-length video i can find of that is https://www.xvideos.com/video10692543/female_condom, which doesn't count because that's lelu love and she shows up on everything