Green’s Dictionary of Slang

(UK Und.) posing as a prostitute, taking the money, but escaping before intercourse takes place.

1977		D. Powis Signs of Crime 178: Clipping Pretending to be a prostitute, obtaining cash, but absconding before any intimacy occurs.
1999		Indep. Rev. 9 Nov. 18: Sleeping in doorways or subways, smoking crack, begging, ‘clipping’ ([...] pretending to be a prostitute, demanding the money up front, and then running away with the cash).