Green’s Dictionary of Slang

1. to ejaculate; thus squirter n., one who ejaculates.

1688		‘Session of Ladies’ in Wilson Court Satires of the Restoration (1976) 211: Her natural mother came in for a snack, / That ballocking squirter and shitten arsed whore.
c.1900		Actionable Offenses Young Cylinder D (2007) [cylinder recording] Do you think that Mary strained or screamed, or did she cry and holler? / Oh no, she let him squirt away and charged him half a dollar.
c.1930		‘Mutt & Jeff II’ [comic strip] in B. Adelman Tijuana Bibles (1997) 14: [ref. to a woman enjoying cunnilingus] Squirt your nuts homey.
a.1969		‘Keyhole in the Door’ in G. Logsdon Whorehouse Bells Were Ringing (1995) 255: But, as I am not like Samson, / Like any other boar, / I’ll simply squirt my gun off, / Through the keyhole in the door.
1970		in P.R. Runkel Law Unto Themselves 52: I’d squirt her four times in les’n forty-five minutes.
1988		‘Victoria Parker’ Incest Schoolgirls 🌐 Then he squirted off [...] Jason shot his wad. His big cock spewed thick gobs of cum that spiraled into the air and came down with slushy splats on his thighs.

2. (US campus) to give a showy recitation.

1856

B.H. Hall College Words (rev. edn) 444: squirt. To make a showy recitation.

3. to confess, to give away secrets.

1972

D. Jenkins Semi-Tough 183: What Cissy did was go squirt off her mouth to Boke Kellum [...] about this book I am writing.