Talk:Sheen/@comment-4636093-20120226022341/@comment-4087140-20120305003607

Activating the ability is what trigger's Sheen to deal extra damage on the next autoattack, not the ability's effect on the autoattack. So when you activate the ability, Sheen goes "oh hey, an ability was used," and so both of the effects take place on the same autoattack.