Ass to mouth is a term primarily used to describe a sexual practice whereby an erect penis is removed from a receptive partner's anus and then directly put into their mouth, or possibly the mouth of another.

Apply the trait to the participant fellating the penis that recently left their (or someone else's) anus. The trait can also apply if a strap-on or another sex toy is used instead.

Use Engages in (Sexual) > Ass to Mouth on the participant engaging in the anal sex and then introducing their penis to their partner's mouth.