Because a woman's chest soft and flexible.
Why Do Guys Fondle Girls Boobs While Making Out?
Thats something ive wondered too.....hmmm.....my best friend thinks its because they want to be having sex with you instead of just making out. And the first time ny bf fondled me, I though he was a HUGE pervert, but after several more bfs, I realized that its just natural to them :P
thansk
It reminds them of their mothers and when they were babies.