Max Malini was a magician who entertained the social elite. He performed for heads of companies and royalty (don't bring bailout money into this, he died over 50 years ago). This trick or "parlor gag" was made by him.
Step 1: Effect
The effect of this trick is that you are at a party and you are chatting with a (insert title here) about (Insert topic here). Suddenly the man says that you have a loose button on your shirt and he thinks he can fix it. Trusting your friend and not caring to check he reaches his mouth down to your cuff bites the button off and displayed it in his mouth. Then he takes it out of his mouth and restores it to your cuff and moves on to chat with another guest.
Step 2: Prep
Get a commen button and thread a string that matches it and put the string on as if you were sewing a button. For those who don't know how to sew a button click here.
Step 3: How to Do It
Walk up to a person and begin to talk to them. Comment that a button on their shirt is loose and without pausing or asking for permission, grab the button and pretend to bite it while gently tugging at it. Then display the button between your teeth as if you are crazy. Put the button back in your mouth while pretending to grab it and commence rubbing the other person's button, comment that is is fixed and begin chatting with another person.