Triangles are harder to get on bigger guys but it will work, don't get discouraged. When putting a triangle on someone, make sure to tighten it first. If it's loose, someone could just slip out of it or defend it easily. You need to grab your leg and make it tight. After it's tight, make sure he isn't trying to stand up and slam you, or get you out of position. You need to keep him down by grabbing his leg and using your hips to push him down. It's hard for me to explain it to you on the internet, but I hope you have some kind of idea of what I'm trying to say....Okay, now you need to push his head down and squeeze your thighs together while pushing his arm across.