At this point, Trixie is referring to his shoulders, not his cock, but her way of getting his tension is going to be through his penis. She sucks his big cock, stretching her mouth around it and getting it wet. Trixie doesn't have any tension to get out, but she is wearing crotchless panties, so Lucas has an easy way in. The panties do come off, and we get pretty explicit views of his dick fucking her shaved, pierced cunt before he cums inside it.