My masturbatrix has a favorite tease technique. She knows I have sensitive nipples.  While I am in a CB2000 she plays with my nipples and arouses me.  Sometimes she licks or sucks my nipples.  She knows how I love that.  She also knows that I can't have an erection, but if my penis engorges it hurts.  She keeps this up for a while, teasing me and torturing me, and if I behave myself, she will finally unlock me and masturbate me to the edge, denying me an orgasm.