Gay Glee Ryder Lynn rehearses Grease with Finn.

When Finn Hudson (Cory Monteith) heard that Glee club was doing Grease, and Ryder Lynn (Blake Jenner) got the lead, Finn went to watch the rehearsal and he saw Ryder sweaty in a tight black navy top and pants, he got horny.
After that Finn invited Ryder back to the garage to test drive Finn's "Greased Lightning".