mc7

First if the skin is tightening for no apparent reason, there's not much that could be besides a yeast infection. That shouldn't ever happen otherwise. (You didn't mention if there might be any further tightening taking place. Hopefully there isn't.)

Any discolored discharge like you mention is not normal and sounds like a very likely symptom of infection. White or yellowish discharge or a lot of smegma are all likely symptoms of yeast too. Greenish seems like bacteria, but I don't know about that really. (Bacterial and yeast infections may occur simultaneously.) I would see a doctor for this if it doesn't just clear up with better washing.

The bad smell you mention is probably the smell of keeping semen trapped under the skin for a long time. Over a period of many hours semen will decompose there without oxygen and smell fishy. This can also encourage an infection if there is one already. But it's really easy to prevent this by at least rinsing your penis off with water before going to bed (after masturbating) to keep the semen residue from decomposing in the urethra and under the foreskin. (It might seem unduly bothersome to have to make this effort, but it really takes only 10-30 seconds, which is a lot less effort than the proper ADA-recommended 2-minutes for brushing the teeth.)

Like I said, I would see a doctor if you have an infection now, but also note cranberry can help too and along with any antibiotics or antifungals a doctor prescribes. Cranberry has some anti-yeast properties. The unsweetened juices seem to be quite a bit more effective than the usual cocktails, but they're almost undrinkable without some kind of sweetener. (I like stevia for this.)

If there's ever an infection (of any sort), I would also avoid milk and cream (even 'non-dairy creamer') and other uncultured forms of dairy as they make it more difficult to overcome an infection. Ditto sweets.