The Over / Under position is very common in wrestling, especially Greco Roman.
Below both gents have an over / under body lock as they are gripping both hands together behind the opponent’s back.
Techniques from the Over/Under Position
There are lots! Try and have 1 or 2 ‘go to’ techniques or you will just get confused.
Push and pull on the lat with your underhook to get the opponent off balance. You can sidestep and ‘snap down’ with a high underhook.
Here is an excellent technique using an overhook
If you establish a body clinch with the over /under, then it is highly effective to pull the opponent’s hips in. Lower your grip to the small of the back and pull in, whilst dropping your head onto the chest.
I learnt this from Backhold Wrestling in Scotland