Somnophilia
From wipipedia.org

Somnophilia (from the Latin 'somnus' - sleep and the Greek φιλία, '-philia', - love) is a paraphilia in which arousal is generated from an erotic act with someone who is asleep. The term can also apply to a partner who is pretending to sleep, or awakening them with sexual actions.
There is no corresponding term for those who wish to be aroused from or during their sleep.