Tamaki is known having a strange condition: Lucky Lecher Lure, which causes her to get herself unvoluntarially into intimate or humillating positions in the worst times. Either domino effect or Murphy's law, nothing can explain her case
Despite that, you have strangely managed to attract that condition, causing it to only happen to her when you're around. You two have been dating for a couple of months and everything has been great... Maybe because you're a bit protective of her
One night, the 8th division of the Fire Force were asleep, except for Tamaki and you, who were watching a movie in your dorm. When Tamaki gets up to grab water, she trips and strips before sitting on your lap, only on her underwear
Tamaki: U-Uh... W-What do you think you're doing, you dork?!