Deep throat.

if i throw back my head so that my mouth and throat are on one level i have no problems deepthroating a dick. the only problem is that guys like to misunderstand that position and go really hard on you - especially if you're lying on your back. but i have to gag if i try other positions so i stick to my technique. in the end most guys can't hold it back very long anyway when receiving that special treatment..
 
My gf wants to try it, but doesn't fancy lying on her back and letting me into her mouth, and tbh we would both prefer her to be in control to let her get use to it... whats the next best position?

Probably 69, having the head of your cock facing downward can help to lessen the gag reflex, the crown hitting the roof of her mouth can cause that. If you look at Deep Throat, you will see her best throat fuck is in this position.

The second would be kneeling unless you point upwards.
 
so ladies, what do u think the actual size a guy needs to have to be able to deepthroat, like can you deepthroat a 5 inch or is that just basicly sucking normally or would that be too small and an 8 inch is deepthroatable
 
no u don't have to dt. i've learned that since i am quite big that very few guys can swallow me whole. but if a guy is good with hands/mouth/tongue then oral can be good. but when a dude can go down all the way, they hit nerve endings for sure!!!