Two adult women from Derry Township near Latrobe, Pennsylvania, have been arrested and charged with having sex with a 15-year-old boy during a pizza party for a group of teens.

Authorities arrested Tonia M. Simms, 37, and Melissa E. Weaver, 26, charging them with statutory rape and other sexual charges with a minor after the victim told police he was solicited by the pair at Simms’ apartment on July 8, CBS News Pittsburgh reported.

The boy testified that during the pizza party Simms invited the boy and Weaver to her apartment bedroom.

Weaver reportedly laughed and urged the teen into a threesome.

“After they were all naked, the child victim said that Melissa looked at him and said, ‘What, you’ve never had a threesome before?'” PA State Trooper John Zalich wrote in his report.

Investigators allege that the two adult women then engaged in a sexual encounter with each other in front of the boy, then brought him into the act.

Simms told police it was initially a joke, but it turned into a big mistake.

“Tonia said that it started out as innocent flirting and turned into a big mistake because they all had a moment of weakness,” the trooper said in his filing.

Bolstering the case, the victim also showed police text communications with Simms in which they discussed his age.

Simms was charged with five counts of statutory sexual assault, one count of indecent sexual intercourse with a minor, a single count of corruption of a minor, and five counts of indecent assault of a person under the age of 16. Weaver was charged with one count of statutory sexual assault, one count of indecent sexual intercourse, a charge of corruption of a minor, and indecent assault of a minor.

Weaver posted a $10,000 unsecured bail, but Simms was unable to come up with the $20,000 cash bail levied against her and remains in Westmoreland County Prison.

Follow Warner Todd Huston on Twitter @warnerthuston or email the author at igcolonel@hotmail.com.