For me, it's the whole shebang.
I like the top, for total penetration, and so that I can rub/grind my clit against the soft mat of his fur, while enjoying anal stimulation from a butt plug (ReadThat: tampon).
And, ladies? There truly IS something wEnderful about using a tampon for that job ~ it won't move around, at the penultimate moment, 'cuz it's sort of dried the membranes, which hold it in place. Until I discovered that, regardless of how much sex I had, which position, or what type of sex it was, I couldn't cum. Also, because they're disposable, clean-up is a breeze!
p.s. Put a SMALL daub of lube on the end, before insertion. (the voice of experience)