Whether you are in a real street fight, MMA Match, or BJJ tournament the over under position will happen every so often. Be sure to study this important position if you wish to be a well rounded martial Artist.
When it comes to takedowns my favourite technique is the double leg takedown, however sometimes you will get sprawled out and have no other choice but to fight from the clinch.
Not knowing how to clinch will result in you getting tired and takedown very easily buy wrestlers or grapplers. Learning how to clinch is essential for all fighters.