No relatives in SC that I know of, but probably all the (Dismukes/Desmukes/Dismuke/ other alternate spellings) are related if you trace the family tree far enough.
Some key points on the Muay Thai "plum" clinch:
- hands grip the back of the head (around the occipital bone), not the neck
- one palm covers the back of the other hand, don't intertwine your fingers
- curl your palms towards you and use your body weight to bend their neck forward
- your forearms are flush against the opponents collar bones. This provides a barrier to help stop the opponent from driving in close for a body lock or takedown and gives extra leverage when bending the opponents neck forward
- squeeze your elbows together, this makes it difficult for the opponent to duck out
- you can make the opponent step the way you want by steering their face (twisting their neck) in the direction you want them to go and stepping back with your foot on that side so that your body weight drags them along by their twisted neck. Right in the middle of their step is a good time to hit them with a knee, since it's hard to for them to defend at that moment
- after you've hit your opponent with a couple of knees, whip them around and break their balance and structure a bit before you throw another knee. If you keep throwing knees from a stationary position, they have a chance to time your attack and catch the knee and try for a takedown
- mix up your attacks, straight knees, curve knees, knees to the thigh, midsection, and head, trips, throws, etc. You can also sometimes let go with one hand just long enough to throw an elbow
- Don't reach to get the clinch, especially not with both hands at once. That's a good way to get hit. I don't extend my arm more than about 120 degrees when grabbing the head.
- When you first grab the clinch, do it with impact - either a forearm strike to the collar bone or a snap down action to the back of the head. That makes it easier to break the opponent's structure.
- don't get so attached to the position that you are unwilling to transition to something else if the opponent starts to escape
There's a lot more, especially once you get into counters and escapes and how to counter the counters, but that should get you started.