MFLB coming tomorrow, need help...

My MFLB is coming tomorrow! if I put a towel under my bathroom door,open the window, and turn on the fan, will the smell be completely unnoticeable after I take a 15 min shower? Like my mom could go to the bathroom right where I vaped immediately after i get out of the shower and not notice a thing? Also, do you hold the battery in the whole time while you are inhaling or only for the first 10 seconds? Thanks for your help Ill post pics of my new box tomorrow, or the next day if USPS messes up my shipping again...