ego-boobst
What guy feels anytime an attractive gal --- especially a "new" chick whom he's only recently met --- willingly allows him to touch her "treasure chest", especially if said "treasures" are fairly shapely/bountiful. The theory, of course, is that such delightful "personal objects" are extra-desirable and thus are surely being actively sought after by many tongue-lolling males, and so the guy figures that he must be extra-special and valued in the buxom chick's eyes if she lets him fondle her fun-pillows, since conceivably she would not allow just anyone access to them.
I was kind and gentle to an attractive plumpish lady on a bicycle whom I met while I was also out cycling, and within an hour or two we were back at her place and she was stretched out on her bed stark-naked and letting me give her a full-body massage... what an awesome ego-boobst!