I mulled this over again and want to take another run at it. Skill in a conflict is important but motivation is more important. This punk is from your friend's family and you will be less intent on smashing him into bite size pieces because of that. Secondly, you are an adult and he's a snot. The adult says "I shouldn't be doing this." The snot doesn't care one way or another. You have two powerful enemies against your success right there. Let it lay.
I'm an old buzzard long past his fighting days. Here's a response that I've used several times:
"Son, you CAN'T possibly beat me.
If you whip me, you have to go around bragging that you beat up an old man,
If I whip YOU, you'll have to live with the knowledge that an old man whipped your asX!"
Just a thought.
Flash
From readint he respnses I am not sure where it was determined that I am "old" lol? Maybe I post that way but I am not that old.
A cuple things have happened that made me ask. My friend has an awesome home where he and his wife have people over and that's why I have been over there. On one occasion a few months into going over his sons was goofing around with his father and they started wrestling (standing up) in the hallway. After the father submits the son gets bored and starts to half jog away. He is jogging past me (I was watching all of this) as if he is leaving and diverts to reach at me and do a half-hearted nipple twister move. Although this was an extremely immature and odd thing to do on his part I did nothing but stand there as he then ran off. His father said nothing.
The second event was recently after church in the parking lot. This one was just verbal but notable. This guy had thrown a few comments out in the past about being bigger than his friends this and that but nothing out of the ordinary. He did say a few things at me at their home but I never took much notice. This time he openly (he does this only when his family is around) made a verbal threat (jokingly) that he would take me on. All I did was turn to face him and kept my eyes on his. He back peddled some and then left to get into his car.
At this point I have made the decision to say something to his father. If I don't and something happens I will always be the bad guy. Good people are extremely hard to find and I don't wish to lose a friend due to his sons immature behavior.