Trust me, I'm a professional at smoking. The best thing you can do is to smoke outside. The wind carries the smoke away and you won't smell afterwards. A little bit of cologne can work wonders, you don't need LOTS(Unless it's a situation like hotboxing your car). And if you can't do anything, always remember this, no matter WHAT condition you're in, NOBODY can ever know for sure whether you're actually stoned or not. Just keep denying, don't give in, and don't turn into a freak.
Another peice of advice, you should get a pack of cigarettes, and smoke four or five puffs, blow into your clothes if you're really worried. The smell of cigarettes almost always overpowers the smell of weed. If you don't want to be a normal smoker, then just don't inhale, and only use a little bit of a cigarette at a time, you could stretch one pack out for a month like that.
The best scent that covers weed is a scent called Patchouli.
Peace.