Well, basically, all you need to do is just act like it's a dorm really. guys are allowed since... well, kotaro-kun and negi-kun bunk here XD.

Main rule: I'm leaving the bunk dorm room making to the members of the guild. if you are a series character... make a dorm for your characters. and make sure you put ALL the girls/boys from the series in the name of the dorm, k?
Second rule: For custom characters, just pm me about having a dorm room. if you want to bunk with someone you know from the guild, just ask and I'll add their name. 3 girls per room, and 1 boy if ever actually agreed to.