hahaha, that's easy! don't mention anything about it to him so you can catch him off guard. spontaneously push him up against a wall and press your body against his and make out kinda aggressively. it would be even better in public somewhere too!
At my house If I am horny and my guy is a bit bummed out from work or playing baseball I just go get undressed and sit by him nude. Doesn't take long and he is feeling a bit amorous and ready to get my hornys taken care of