I started a thread about it a while back:

Evil stench from dried spunk!

I noticed that people don't like to admit that they get that bad smell, but the thread got many views so I'm sure that it a common problem.

The only solution is to wash your glans as quickly as possible after ejaculating. Otherwise washing several times afterwards is the only way I know of reducing the smell, for some reason soap or anything else isn't good enough to eliminate that smell in one go.