The dude on the bottom was going for things. Not sure if he ever traned UFC or if its from watching fights on TV.
Not trained IMO. 
hahah that fool just watches "UFC" and thinks he knows a few moves. This should also serve as a reminder to never throw a sucker punch with your pants sagging. idiots...
ShieldsWrestleBangedMySN - Not trained IMO.
I kow he isnt trained. I am wondering if he is traned.
Kimura from the bottom didn't look bad (beep).
Also, lol at the butt-punch combination at the end. Nice.
Guy with guard bottom has probably has some bjj training, although not much.
YukiNakai'sEye - He's probably a legit black belt but these are the streets motherfucker.
Not quite piano belt. Maybe ukulele belt.
YukiNakai'sEye - He's probably a legit black belt but these are the streets motherfucker.I change my answer to this. He is a legit black belt that has been punched in the face exactly 4 times before the video started.
Why did he throw a combo to the black butt?
Lmaoo Thats a huuuge butt!! It can take a beating too.
Cecil Peoples has it 30-25 for the dude with no pants
Col Angus - Why did he throw a combo to the black butt?
Can't waste a good combo, I guess.
Id bet money troy(the white dude) was a high school wrestler. Black dude was about to kamura his ass though before the standup.
Those black guys are going to get their bro card pulled, getting beat on by a bunch of white boys like that.
Butt punch. That just happened.
I truly lolled. Black guys a white belt. He was trying to reguard ok when he was getting passed. Shit got hilarious at the end
My ultimate funny construction video
Col Angus - Why did he throw a combo to the black butt?
Holy fuck. I just laughed like an asshole at work. Watching buddy throw a few punches at the full moon was the funniest shit I have seen in a long time.
Many BJJ guys never have someone bigger than them on top throwing down punches, this guy could be more seasoned than you think. Many dark colored belts fall to pieces once you ball up a fist. Also his guard wasn't that bad, he only got hit cleanly to the face a few times and by the end had the guy tied up pretty well. 
I'm pretty sure DantheWolfman showed off 'the butt combo' in one of his videos.
Brian McLaughlin -Many BJJ guys never have someone bigger than them on top throwing down punches, this guy could be more seasoned than you think. Many dark colored belts fall to pieces once you ball up a fist. Also his guard wasn't that bad, he only got hit cleanly to the face a few times and by the end had the guy tied up pretty well.
this^^ he almost hit a couple of things that could have ended the fight. however looks like he had an adrenaline dump or the effect of theres a guy who seemed bigger and stronger trying to take his head off fatigued him. but he obviously had some training