Don't straddle my foot

[Dexter]

We have a 10month Cockapoo puppy. He straddles my foot when I am sitting down with legs crossed. He leans up against my legs even pushing against them. I read that this is a dominance behaviour. But so much else of what he does is so submissive (I think). He only does this to me, but did it to a male friend I visited with the dog. He doesn't do it to spouse and adult children in the house. He rolls over on his back whenever we approach to have his tummy stroked. He sleeps on his back often too. He is obedient in not going upstairs and mostly in other things around the house. Eg dropping things when told to, or getting his nose out of things he shouldn't investigate. He doesn't mind when I hold him down in a similar way to how I saw a Pointer we met on holiday dealt with him in a very dominant way. He only growls in pulling games (which I always win). He looks away when I look at him, not holding my gaze in a challenging way. This doesn't seem a sexual behaviour either. He is not neutered.

Any explanation or suggestions?