Term used in South-East London meaning you have someone doing whatever you want. Nb. often it will simply be a comeback when nothing else is able to be used.
To have someone on smash.
1: Get a drink for me please.
(2 gets drink)
2: There you go.
1: SMAASH!
1: You're so ugly!
2: SHUT UP MAN!
(1 is unable to respond)
2: SMAASH!
1: My maths teacher was so annoying, but it was aite coz I had him on smash.
(verb, intransitive) To engage in quick, vigorous and unbridled sexual intercourse. Frequently ends in premature ejaculation and tears.
It should be noted that "smash" is an intransitive verb and should never carry a direct object. (despite what one may read on the internets) One should never say "She's so hot, I'd smash her all night." Rather, the object is implied by the context. "She's so hot. I'd smash all night."