Ok, i stash my stems and seeds in a beef jerkey can. It looks like the size of an altoids can. That's the best place to store them. Throwing them out could work too. May be risky depending on where you live and everything.

Your friend eats them? He is by far an idiot sir. Why would you EVER wanna eat stems and seeds? That is sick.

NEVER, EVER SMOKE STEMS OR SEEDS!! That is horrible for you. People that leave seeds and stems in their weed piss me off. It does not get you high and it taste like shit. Also, it seems to burn a hella lot too. That's a bad thing to do. Always remove it from the weed.