The Sex boulder is a large boulder at Invasion with routes on all sides.  The surrounding smaller boulders around the base host some classic problems.  

Follow directions and approach beta for Invasion crag.  The trail, starting at the road, goes downhill and sharply to the left.  This bottoms out in a hallway with the cliffline on your left and the sex boulder on your right.  After passing the sex boulder, the trail goes up briefly, where you will class a boulder with the old classic problem "A Dream Come True." After passing this boulder, you will cut right and do some scrambling through another hallway between giant boulders.  When you get through the scramble, Ab Lounge should be plainly visible on your right.  Electrallica will be on your left.  If you dont want to scramble, you can bushwhack a bit and go all the way around the giant boulder making up the left side of the hallway.