Green’s Dictionary of Slang

a body piercing performed on the penis, usu. a small bolt through the glans.

1999		Indep. 21 June 16: A Prince Albert is an item of jewellery I’d rather not talk about.
2002		Indep. Rev. 19: Those who (if given a bicycle) would immediately disassemble it to create four novelty steel sex toys and a Prince Albert from the chain.
2003		K. Cage Gayle 53/1: Albert n. (abbr.) (Prince Albert) piercing of the glans of the penis with a metal ring. [Ibid.] 87/1: PA n. a Prince Albert piercing through the urethra of the penis.
2005		Observer 6 Nov. 3: According to various gay chatsites [...] he – allegedly – has a ‘Prince Albert’.