I'm not sure why it never caught on over here...It is rather useful as both noun & verb..(I never even heard the term until I'd been online a couple years.)
I do know that masturbation was not a common topic in MY youth...at least in the crowd I was around. About the only term I have ever heard as an adult is 'jerk-off', and it never seemed to be used in the half-kidding way that 'wanker' seems to be used in the UK. It was mostly used to refer to someone NOT present.