This is how we do game night at my house. I always purposely lose just so I can watch my wife get fucked by all my friends. I cum harder when I watch all of them use her and cum in her then I go last.
For me it's always been REALLY simple: whenever another guy is better hung than I am, I suck him off, & I enjoy having women watch me 'cause after SO much 'practice' I'm a better cocksucker than they are.