I smoked a bowl with 2 other people after drinking about 5-6 beers (which is nothing for me) but for some reason, I was FUBAR and I couldn't even walk right.
Grass before beer, you're in the clear.
Beer before grass, you're on your ass.
For some reason, smoking when you're drunk, but not already stoned, seems to have unexpected and bad results like this a lot. If you get high while only buzzed, you can keep smoking all night, but if you don't get high until already pretty drunk, you get really fucked up in a rarely pleasant way.