LYNN – It wasn’t John Duffy’s lucky day.Duffy, 74, of 136 Walnut St., Lynn, was arrested after being caught with his pants down in a car behind Lynn Vocational Technical Institute near McManus Field around 6 p.m. Saturday.Police say he was engaged in sexual intercourse with Jean A. Powers, 56, of 931 Western Ave., Lynn while the car was parked approximately 40 feet away from a group of teenagers.According to police, Officer Shawn Hogan was on patrol when he decided to put a stop to the unsanctioned physical education lesson.As the officer was patrolling the Lynn Tech parking lot, he reported seeing a man’s buttocks in plain view in the passenger’s window when he approached the vehicle.After Hogan allowed the couple in the car to make themselves decent, the female, later identified as Powers, gave the officer several different names and appeared to be agitated, according to police.Hogan asked Powers what day she was born and she replied, “7/26/85” to which Hogan asked her to tell him again.She finally yelled, “I was born in ’51, you happy now!” according to police.Duffy allegedly told police he met Powers at the bar at 595 Summer St. a short time earlier and said he didn’t know her name. Both Duffy and Powers said no money was exchanged for sex.When asked why they chose to engage in sexual behavior in an area frequented by youths, including the 15 or 20 teens currently nearby, Duffy answered, “They weren’t here when I first pulled in,” according to police.Before the pair was transported to the Lynn police station, officers had a tough time determining Powers’ true identity because she gave several different aliases. Police said she appeared to be highly intoxicated.Both Powers and Duffy were charged with lewd, wanton and lascivious conduct and disorderly conduct.