the first time that hux and ren have sex, ren comes immediately. hux is displeased, to say the least, so he puts ren through a training regimen of sorts to build up his stamina: hux sits and watches ren jack himself off and tells him when he can come; they build up his stamina from there by slowly introducing more and more physical contact (hux kisses him, hux fondles him, hux blows him, etc.) until ren can last long enough for he and hux to actually fuck again.