/cm/ is a board on 4chan, primarily dealing with cute males, for which the board is named. /cm/ has many pics of lovely anime guys all over each other. The anons here consist mainly of gay men and yaoi fangirls.
/cm/ is closely related to /y/, the yaoi board. What differentiates the two is that /cm/ is SFW, and /y/ is NSFW. Therefore, showing of genitals is banned on /cm/, and should stay on /y/.
Ariana: Hey did you see the giant Durarara thread on /cm/?
Wes: Hell yes I did! It had all the best hot guys!