A sex act in which a person (male or futanari) has their penis rubbed in the cleavage between their partner's breasts. Also known as titty fucking or mammary intercourse. On Danbooru the Japanese term 'paizuri' (ぱいずり) is used.
If the penis is long enough, fellatio may also be involved at the same time.
If "paizuri" is performed on an object that is not a penis use simulated paizuri instead.
