With such ample peen on display, you may wonder if you’ve stepped into an elaborate version of a homoerotic peep show inside The Loft at the Davenport Theatre in Manhattan. Actors Brandon Haagenson, Patrick Reilly and Robbie Simpson are certainly chiseled and handsome, yet watching them cavort in the nude throughout much of “Afterglow”is more thought-provoking than titillating. That’s because first-time playwrightS.