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 instead of a penis, use the tag "simulated paizuri" instead.
