There's just very few people who understand and use the full Thai style of clinch work in MMA, so unless you train with one of those folks it's hard to learn how it works, how to use it, and how to defend against it. Which is strange to me since I've seen a fair number of UFC fighters doing training camps in Thailand or bringing in trainers from Thailand, so you'd think they'd be learning real Muay Thai as well as how to use the clinch.
Matt Brown and Valentina Shevchenko are the only ones I can think of who use the full range of grips, striking, and grappling techniques in the clinch. Valentina is pretty easy to explain, but I'd like to know how Brown picked up his clinch techniques.