Hmmm
I was laughing so hard when he told me I didn't really give much thought to the practicalities. I'm guessing that it was either an extremely large but soft breast that was 'fed' into him in increments or an ultra-firm, surgically-enhanced torpedo of a boob that just blasted its way in.

Or perhaps there wasn't a huge amount of penetration but he was wanking and that, plus the fulfilment of a perhaps long-held fantasy, was sufficient to bring him off.
(Happybara The jungle came alive and took him, Tue 11 May 2010, 11:06, Reply)