butt string 

usually a peice of cloth that has been inserted into the anus on a warm day.
b. when string from a towel and or underwear, stays in buttcrack for more than five minutes

I took a shower and felt some butt string hangin out.

butt string by wannafanta May 11, 2008

Spring-Butt 

That one guy in class that seems to know all the answers, and is jumping out of his/her chair to impress everyone with their knowledge.

Bill is such a spring-butt that he ran to John to let him know the solution.

Spring-Butt by SB#1 October 12, 2008