Keep Calm and Cowboy

If love is friendship set on fire, sex between best friends is a torch to tinder.

In second grade, he asked her to be his girlfriend. She said yes, and that was the end of that.

Keep calm and help a girl out:

Fourteen years of friendship later, Colin relishes living up to his reputation as a player, until fooling around takes priority over his grades. Losing his scholarship gets him booted out of college and lands him back home on the ranch with some strongly worded advice from his dad about staying away from women. Speaking of women, though… He's barely ever noticed his childhood pal Violet is female, let alone one he'd like to get horizontal with, but now that he's back, he can't seem to think of anything else.

Keep calm and learn from the best:

When none of her relationships move past first base, Violet knows she's doing something wrong. Lucky for her, Colin the Casanova is back in town. He seems like a natural choice to tutor her, until she realizes he's the only guy she's ever wanted to get physical with. Too bad they agreed they'll go back to being friends once her final exam is over.

Openly dating would destroy both of their reputations and break up their group of friends, so they have to finish this ride through the last lesson, then keep calm and cope.