Blaine and Sebastian have set up Greg to be caught in Blaine’s bed, in order to blackmail the football player into discerning who told Annette about Sebastian’s reputation.

In the aftermath of the blackmail, the sometimes-lovers fight. Greg is shocked that Blaine set him up, while Blaine is angry by Greg’s hot-and-cold treatment. It is clear that, for as much as both claim their relationship is only about sex, they both have genuine feelings for each other (something not explored in the film, where they have substantially less screen time or development).