Everyone knows someone like Jason, the protagonist of David Rosen’s endearingly hilarious debut novel. A marginally employed 25-year-old in search of the perfect buzz — and maybe a chance to give Little Petey (yes, he’s named his penis) a workout — he’s a Manhattanite on the prowl, a slacker who blurs the line between sweet and annoying. His friends are getting tired of him. After all, they’re beginning to couple, pursue careers, and settle down, and Jason’s “you won’t believe how wasted I was” stories are getting old. Even his indulgent middle-aged neighbor, herself a party girl back in the day, is ringing cautionary alarms. But what’s a guy to do? Jason’s search for his place on the planet includes numerous sexual trysts, one with a woman who makes off with his favorite jeans; a night of debauchery that literally lands him in the gutter; and brushes with both religion and mortality. While the optimistic ending is predictable, this barely matters. Instead, raunch meets redemption in this wonderfully observed, breezy and entertaining story.