Doggie is good for when the sub needs to be
taken
Spooning sideways is good for when there must be gentle pleasure for both involved...
And hey, if (s)he begs but i'm (finally) tired? (S)he can ride me and get us both off that way.
Deep penetration though - and this is probably not a position you can do with all partners as they need some agility - is in my opinion best achieved by kneeling with their rear end in your lap - while they lay back. The higher you sit up, the deeper you can penetrate - and for some extra pleasure, bring their legs together, knees in front of you.
Particularly in girls this seems to create additional sensation...