Sperm fires at such a force, if your on top, bent over on on the bottom, it will still shoot the same way.
Im pregnant and i was mainly on top during 'it' lol. So i dont think it matters.
As long as your ovulating and in your fertile window it should be fine.
Of course you could always lay down after and put a pillow under your bum?
Sorry about how i said it, but there is no other way to put it lol.
