also: やりとも
fuck buddy; friend with benefits
Vulgar slang for a friend with whom one has a purely sexual relationship, without romantic commitment.
He's not my boyfriend, just a fuck buddy.
A fuck-buddy relationship is easy because we keep it strictly physical.
Hiragana variant; less common but still used.
Compound of ヤリ (from 遣る, 'to do' in the sexual sense) and 友 (とも, 'friend').