Thomas: Tom/Tommy. Most of the time, you call Thomas by his actual name. But when you guys are having intimate moments and such, ;) you tend to call him by nicknames.

Minho: Sass Man. You call him this when you and Minho are having sarcastic fights and playing around.

Newt: Newtie/Newtie Cutie. You call him these funny names when you are in front of the gladers or his friends. He likes it when you tease him, but sometimes you do it at "inappropriate times" as he calls it.

Gally: Captain. You personally do not care for nicknames, but Gally insists you call him Captain. It makes him feel confident and empowered.