When you first sail to Muffington Island, talk to Otis to your right and exhaust all dialogue options
Walk up to the Village Center and walk towards the women to get thrown back in jail
Click the door on the far left to talk to the guard again and exhaust all dialogue options
Take the exit on the left to the Village Square
Walk to the lower left corner to the Village Entrance
Talk to Otis
-That Wendi girl finds you interesting...
-Your barbaric tresses!
-Your sonorous, powerful voice!
-Your penetrating masculine gaze!
Now... sigh... take a photograph of Otis' crotch. Walk up to the Village Center and walk towards Wendi to return to jail
Click on the door on the far left to summon Wendi again
-I have a photo here that might interest you.
-I won't tell if you take off for a bit.
The next section will have you looting the Village Center and the Cemetery to the right. After you've done all that, exit to the right to the Village Center and then go lower right to the Village Entrance. Click in the upper left-hand corner to go behind the hut and unlock the WENDI LOVES OTIS achievement.