Detective Dennis O'Connell said the behavior, referred to as "gooning," involves "largely a male individual going into a store - more recently, it's been kind of more apt to happen in a Dollar Tree - and it's where an individual then fondle themself and/or expose themself to usually female customers."
O'Connell called the acts "very disgusting" and said the most recent incident occurred Tuesday afternoon at the Dollar Tree on Plaza Boulevard in Morrisville. Police are asking for the public's help identifying a man seen wearing a Central Catholic T-shirt.
Shoppers expressed frustration and concern.
"It's a shame. It's disgusting. This is where families go, so nobody should be exposed to that," said Erin Byrne of Yardley.
Bill Kauffman of Ewing said, "This has always been a good store since I've been coming," later adding, "Everybody is losing their mind. It's crazy."
Middletown Township police reported a similar incident Wednesday afternoon at the Michaels store on Lincoln Highway.
Investigators are working to determine whether the same man is responsible for both cases.
O'Connell warned that such encounters "can definitely lead to long-term traumatizing effects for anybody exposed to this."
He urged shoppers to stay alert and avoid engaging with anyone behaving inappropriately.
"If you do see this type of activity happening, don't react to these individuals. Definitely don't approach them. The best thing to do is simply walk away, and as quickly as possible contact police," he said.
Falls Township police are coordinating with other departments and looking into whether the incidents are being posted online.
Action News also reached out to Dollar Tree about possible security changes, but we have not heard back.