I know I am not a guy, but since it's one of my favorite things to do... I can say the most reaction I get is from the Base of the sack and the taint. Originally Posted by Reese FosterReese you should hold seminars on this topic - not to mention the rest of your open-ended menu.
I don't get out much, but using the same techniques aimed at the same locations on the ladies seems to get a wonderful reaction too.
Until the hobby I never thought of my balls, sack, taint and ... well, you know (Reese's euphemism, not mine) ... as centers of sexual feelings and target arousal areas.
Back to the OPs question - mine are equally sensitive, licking is my preference interspersed with some gentle ball sucking. The further back you go, the more I'll squeal like a little girl.