Green’s Dictionary of Slang

fisty palmer n.

In phrases

have a date with fisty palmer (v.) [play on SE fist + palm]

to masturbate.

2003		Indep. Rev. 1 Oct. 5: My friend’s sexual ambitions were doomed to end in a date with Fisty Palmer.
2003		Number One Adult Sexual Health Terms Advisor 🌐 Masturbation Slang Male Terms: [...] date Handrea or Palmela or Fisty Palmer.