When anal penetration is about to occur, but hasn't happened yet. This includes sex, sex toys, tentacles, fingering, or any other type of penetration.
This tag is for nude characters, use dry humping or bulge to ass for clothed situations.
If the penetration is non-consensual, tag imminent rape.
Try not to confuse this with after anal, which may look similar to this in small thumbnails.
This tag implicates imminent_penetration (learn more).