eff(v = verb.contact) bang, be intimate, bed, bonk, do it, fuck, get it on, get laid, have a go at it, have intercourse, have it away, have it off, have sex, hump, jazz, know, lie with, love, make love, make out, roll in the hay, screw, sleep together, sleep with - have sexual intercourse with; "This student sleeps with everyone in her dorm"; "Adam knew Eve"; "Were you ever intimate with this man?"
is one way to copulate, couple, mate, pair
Sample sentences: Somebody ----s

eff, v. sl. euphem.
1 tr. & intr. (often foll. by off) = FUCK (in expletive use).
2 intr. say fuck or similar coarse slang words.

Idiom:
effing and blinding using coarse slang.

Etymology:
name of the letter F, as a euphemistic abbr.