Sally finaly gave in to my advances last night and agreed to have sex with me but I was unable to perform with vigor and vitality because I had limber timber.

You gotta limber up
Means: you gotta get more agile :

That guy was such a "limber dick" at that party last week.

Bill: Seriously?!? Johnny touched his toes!!
Fred: Are you kidding me?
Bill: No, not at all, Johnny is the local limber potato.