Due to social constructions around masculinity, men are typically saddled with the expectation of initiating, pursuing, and escalating the relationship physically. To subvert those pressures, take it upon yourself to show how much you crave him by making the moves and showering him with flirty attention. Be forward in letting him know he's the object of your desire.
It is always pleasant to be awakened by such a boner, unfortunately the only time a similar situation occurred to me he immediately released his load in my hand...