The practice of one, entering another's asshole without consent and stretching out to occupy the most space. The sole purpose being to damage one as much as possible.
Thor: Yo team I totally ant-manned this Asguardian hoe last night.
Tony: Wtf is Ant-manning...?
Ant-man: When youjump in someone's ass and EXPAAAAAAAAAANNNNNND
A person or an unwanted friend who pms's for absolutelyeverything, with one of his hand busy with the phone n the other on his crotch to ease himself with the pain from bleeding.