Mans G spot

So I found out a few days ago that a mans g spot is up his bum. After doing some online research, I read you can literally give a man the best orgasm ever by rubbing the lump up his bum. I like to please, so I thought I'd approach my husband too see what his thoughts are on this. Basically he seemed really grossed out and said its an exit not an entrance for him. I feel silly now but how would he know he doesn't like it if he's never tried it? I think he just feels uncomfortable about where my finger would go! Has anyone else done this with their partner and did he enjoy it?