Same way as you did when you first started riding things you don't like, keep at it. Ok, what mimitabby said. It comes back but sometimes it takes a little bit of trying and a little bit of having your mind happen to be off topic when you go through it to the point you don't really realize 'til you've already got by.

Like when you're chasing someone down the trail and there's no time to think.

Hope your friend is doing well.