Mom of sons here. Some boys stink. I am hyper aware and my boys shower daily and I enforce the deodorant rule. They only get stinky occasionally. But some boys do stink on a regular basis. I'm not sure why. Do they shower regularly and use soap? Deodorant? Clean clothes? Clean sheets? Stay on top of hygiene and smell will be greatly reduced. good luck
There is a wonderful 'thing' called Febreze it works, very well indeed, on Airborne smells. Just a thought.
It could be because there's two adolescent boys sharing a room?
Active 15-year-olds generate a LOT of perspiration ALL OVER THEIR BODIES so yes, they do need to change clothes daily, and with twins, you're going to have twice the smells. Are they "spunking"? Most likely - and somewhere in their room are two towels or wash cloths that are in desperate need of being washed. Relieve some of their anxiety - and some of yours - by telling both of them that, if they are "spunking", you're not going to alert the newspapers and radio stations or have them arrested for doing something entirely normal for teenagers but it isn't healthy for them not to clean whatever it is they're using to wipe themselves off afterwards.