I also agree with everyone else that you should take your boy to the vets. However, my 2 occassionally vomit after eating - the vet believes it's because they are food guzzlers... i.e. they barely stop eating to take a breath. Despite being a healthy weight and having adequate food quantities, there is little I can do except feed them smaller amounts more frequently.

I hope this is all it is with your boy, and nothing more sinister... Good luck and let us know how you get on.