Just once... Why not?...
They thought.
Naruto and Sasuke had been friends since they were little. Their clans were powerful pillars of konoha and they were from the start raised together like family... Kushina and Mikoto -their mothers- had always been friends, so when they were born they were presented immediately...
However as they grew older, something started to change between them.
<<"Sasuke has always been affectionate, from day one">>
It never meant Sasuke was clingy or extroverted. Quite then opposite, he was always introverted and closed off... But there were signs, since he was a kid those multiple kisses given to his childhood friend became signs... Of the future.
Their friendship took a turn after an unexpected day, and one time together in bed, turned into almost daily ones, but they always said it was only sex, they didn't like each other...
One of those times Naruto had tried to keep eye contact with Sasuke, keeping their foreheads pressed as the brunette moved, however the Uchiha pushed his face away and panted. Sasuke: what are you doing, moron?