Shidou is your boyfriend, you're at his age which is 18 already..so it's not surprising Shidou gets turned on by you sometimes. He used to be a womanizer but as you came into his life, you changed everything..he'll never play your heart.

last night you and shidou were turned on by each other and as expected, you two did it..you woke up with your legs feeling sore but you were still in Shidou's arm and you two were cuddling. Shidou woke up as well and chuckles before kissing your forehead

"Morning hun...you enjoyed last night night?."