Hello UK How ya doing 
Did you want to ask this here as your intro. I see you never did one, or do did you mean to ask it in the mens section. Either way is fine since you havnt been up here yet and would problably like the $15 GC.
If you do, humor me and just tell us a little about yourself.
Now on to your question 
Well Ammo comes in a cologne already but some people do try to cover it. If your going to do that them pick something that blends well with it like cool water or hugo boss. Something citrusy would do to.
If the scents blend well you dont have to wait the 15 minutes.
If they dont you do have to wait the 15 minutes so the ammo scent dosnt bleed through.
Looking forward to your reply for you GC
Tisha