DS had a cold last week but still is trying to cough up a lot of mucus. Is it something I just have to wait out? I get scared sometimes cause he chokes and I have to smack him on his back. He tries to cough it up but it's just not coming up. He never got a fever...just coughing, sneezing a little bit of a runny nose. He's only 3 months so I don't give him anything. Any advice?

vaporizor in room, keep him sleeping elevated with head up...prop on his side to sleep instead of his back to help avoid choking, vicks on chest/throat a little, warm bath in a very warm room to help it drain and you can wipe a lot of it away....
Actually, the more they spit up with this stuff it seems, actually helps them many times...