'Coitus mammaris'. "Giving her a pearl necklace". Or......titty-fucking. (though I'm open to hearing others. 'bangin' boobies' perhaps? ) This seems to be extremely popular, though for me it's one of those things I'm more than happy to write about, but much less enthused about trying. Of course part of that is due to my own personal limitations, but even when such a thing was possible, I never even suggested it and would likely decline had it been offered. I just don't see the appeal.