What would you do if your parents were really drinking!
I suggest when you're standing while addressing them, just casually rock to the left and to the right on your feet. Just a gentle, almost non-noticeable sway. It should really mess with them. Then when they've had enough and tell you, that's when you come out and make your point.
All fun aside, don't waste your time talking to them until they sober up.
Be the example! and let them know what it does. SERIOUSLY! Show them. I have an uncle who drank a lot but didnt always get drunk, hed just throw up sometimes, rarely and now he has ulcers and is pooping blood and has HUGE pains in his stomach. hes dieing... just make sure they dont over do it!
my dad drinks, and he takes it out on me, but im moving out :D so yeah, he's an ar$ehole basically.