This is different from imminent vaginal. There, the head of the penis is directed at the vaginal cavity with the intent to penetrate. Here, the female's pussy is simply rubbing against the penis without actually penetrating. The key visual difference is that the penis is more or less directed in a horizontal position against the pussy so that it can't penetrate like the vertical position can.
For ass-to-penis rubbing, use buttjob instead.
For pussy-to-object rubbing, use crotch rub instead.
For pussy-on-thigh rubbing, use thigh straddling instead.
For pussy-to-pussy rubbing, use tribadism instead.
For penis-between-thigh rubbing, use thigh sex instead.
For rubbing against anything else, use frottage.