Ummm just stop what's making him feel embarrassed and move on. If it's something he must get over with, sometimes you gotta wait till he feels ready.... sometimes a good push is all he needs :)
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If you call him on it in a public situation, he might get defensive. The best thing to do would be to take him aside and say, "Look, I really don't appreciate what you've been saying/doing. It embarrasses me."
Just sit down with your boyfriend and have a heart to heart talk with him. If he's a good boyfriend he'll understand, but his reaction might also depend on what kind of embarrasing you're talking about. ;)