on :ACTION:$($+(,$me,*)):#: {
describe $chan slaps $nick around with a bit of a large trout.
}

That would react on all of the actions made toward you.
or:
on :ACTION:slaps:#: {
if ($($+(,$me,*) iswm $1-)) {
describe $chan slaps $nick around with a bit of a large trout
}
}

That would react if slaps is in the text and your nick was mentioned.