Tone it down! Isn't it toned down enough already?
It's not the facts of the relationship. It's the descriptions you use and the tone you imply:
'It was a backless dress made of flimsy, clingy material. It was already short but the occasion called for making it shorter. Jack deserved the VIP treatment.'
'Off came everything I wore. I put on thong panties but no bra and slipped on the dress. It reached only to my upper thighs. String shoulder straps held the nearly weightless thing up. My back was bare to the rump. Cleavage exposure ranked a venial sin. I looked in the full length mirror on the door. Yup. This was the ultimate killer dress. “Jack, eat your heart out!”
'We went downstairs and when the boys lingering around in the hallway saw us them whooped and hollered in exaggerated manner. They were paying tribute to my appearance'
'I was conscious that they were all thinking of my body. Well, some girls might not like it, but I did. Let prudes go to the beach and then say I was being slutty.'
You have to read them from a YA perspective. I know I can.