round-robin, v. — Green’s Dictionary of Slang

round-robin v.

[SE round robin, a sports tournament, e.g. tennis, in which each competitor plays all the rest]

to have sex on a single occasion with a succession of partners; also as n.

1960		G. Swarthout Where the Boys Are 179: Dilworth [...] had taken her to a motel for some shack and got her drunk; enter the other two, who tried to make a kind of obscene round-robin out of it.
1986		L. Heinemann Paco’s Story (1987) 36: That pudgy little nymphomaniac who round-robined some semi-pro football team, between Denver and Santa Fe.