Does anyone go to as tanning salon to keep up your no tan lines?

My wife was given a coupon for a free week of tanning at a salon that had to be started before the end of 2015. She gave it to me so i went to get it started. The woman said I should start with a 15 minute session instead of the full 20 which I did. Since my bottom had not seen the sun in a couple of months on a regular basis I should have probably started with 10 minutes. Now it's a little uncomfortable to put on shorts. Not only that but the woman neglected to tell me that I needed to pull the top down when i got in the tanning bed so now have a severe tan line on the side of my butt which was the opposite of what I went there for. And since I only have a week to tan I don't know if i will even make it back for another session in time with this burn. Anyone else ever have this problem?