Sven and Ole go to the beach.  Sven always has luck with the girls, so Ole asks for advice.  Sven tells him to stuff a big potato in his trunks and parade up and down the beach in front of all the girls.   When they meet an hour later,  Ole complains that he's had zero results.  Sven says: "Ole, you have to put the potato in the FRONT of your shorts!