FRISCO -- Dak Prescott called his Thursday at The Star "frustrating" and "fun."The Cowboys quarterback was one of 12 head coaches at the team's annual Cowboys U youth football event, which usually marks the end of organized team activities. His 7-on-7 team didn't finish with the record he was hoping for.Things, however, went a little better for him and his teammates during their three weeks of OTAs."We got a good feel for one another," Prescott said.