For months, they thought Shannon O’Connor was the adult in the room. As far as they knew, their 14- and 15-year-old kids were hanging out with the Los Gatos mom’s charismatic freshman quarterback son, playing ping pong and swimming at the family’s $4.7 million French Colonial-style home in the hills. Little by little, their kids’ strange behavior hinted that something disturbing was going on. They eventually discovered how O’Connor had befriended their kids on Snapchat, luring the teens to parties with their favorite beer and showering the girls with roses and jewelry from Tiffany & Co., even whisking a group off to a secret alcohol-fueled party at Lake Tahoe. Now, interviews with three of the parents reveal their astonishment when they discovered what prosecutors say was really happening: A 47-year-old social-media-savvy mom had manipulated their kids into frequenting a party house of underage binge drinking and drunken teenage sex. “It just infuriates me,” one of the girl’s mothers said.