You're a saint for having sex with my brother. No, really... It's like taking a bird with a busted wing and putting him in a shoebox and feeding him with an eyedropper. You know he's never gonna fly, but you give it your best shot. Alan's the bird.
Explanation:
Drunk Charlie came into the room to Alan and Lynsey, who were having sex and distracted them. Shaming Alan in front of Linsey.