at least "bg masturbate pillow (22)" is used and can be reached in a legal play-through w/o shenanigans , the reason I noticed it (and started the linter to take a more systematic look): Riding pillow -> Nude -> Scarlet joins -> 'Do you want to join me'. renpy tries (and fails) to load it in masturbation_new.rpy:311.
and seriously: lint is your friend :D