A personality trait that demonstrates strong decision-making skills or control, characteristic of homosexual males who prefer to be on top. Often valued by men who want to relax and not make choices (see, e.g. bottomy).
Where do you want to eat tonight?" "I'm not feeling like making decisions tonight. Just show me your topside and pick.
The Act Of Landing a Left/Right Hook straight onto the side of someone's head, when done effectively knocking onto their ass. (Top/Head, Side/Hook).
'If this prick keeps pissin me off then he's gettin a straight topside slap'
Jack - 'There was this right prick in the club last night'
Jon - 'Oh Yeah what did you do about it?'
Jack - 'Oh you know me, Just gave him a topside, that shut him up'
'Dont Watch That You'll Get a Topside' - Dizzee Rascal