There are several ways and grips to set up the Peruvian Necktie. This is how we do it in the 10th Planet Jiu Jitsu system. You can't have your hands too tight or they will pop off when you sit back and throw the leg over. This is a very tight choke which comes on in less than 3 seconds.
The Suicide choke is a very tight and fast choke to apply from when your opponent is in the turtle position and you have cross side position. The full body weight will be applied to this choke, hence the reason it comes on so quickly.
Stephan Kesting from http://www.beginningBJJ.com takes you through the five fundamental triangle choke variations, including those used in MMA by Brock Lesnar agains Shane Carwin, Chris Lytle against Matt Brown, and Fabricio Werdum against Fedor Emelianenko
Robson Moura demonstrates a great jiu jitsu technique, moving from knee on belly from side control, with belt control to a far side armlock or joint lock. If this doesn't work, transition to an omoplata for the next submission.
Sometimes guys are tough to tap out - try out this nice combination attack, a loop choke from inside an opponent's sitting guard, to a follow up loop choke from turtle position. Technique presented by black belt Dennis Asche of Connection Rio and Gordo Jiu-Jitsu.