Does "May I touch your lovely boobs?" sound any more derogatory to you than "May I touch your lovely breasts?"

No, although my answer to the latter would undoubtedly be "no" (barring context) and my answer to the former would probably be to point at my friends and say, "I don't know, you'll have to ask them."

(And I agree that the word "grab" is the problematic one in that sentence.)