What would you think if I told you I slept with my best friend?
Is there a reason that you slept with your best friend?
I felt that it was the right time to do so.
There is nothing wrong with sleeping with your best friend, as long as you both have consented to it. Maybe it could turn into an exclusive relationship, if that is what you both want.
We're just friends, just friends.
As long as it's something you both wanted to do, it's fine to be friends with benefits. And if it was a one time thing, just don't let it ruin the friendship.