Um... I don't pull it any tighter than usual. I even loosen it up throughout the day.
I don't recall using anything with mineral oil either....I use castor oil to hold overnight and a little Eco styler in the morning when needed.
Before I flat ironed I had three strand twists in and the night before that I went to sleep with my hair lose...no bonnet and no ponytail but as soon as I washed and flat ironed the bulbs disappeared.