not entirely sure if it plays into it but i think during the route you have to compliment Spencer's looks and admit to Dwayne that you find Spencer attractive. but most off all during the sleep over on day 20 you have to strip down to your underwear and then admit to Spencer himself that you find him attractive when he asks (basically during the route tease him and flirt with Spencer every time you're given the choice)
Go back to page 32 for the guides for the main routes; Chester, Harold, Darius, Spencer and Dozer. The Guides for Richard and Dwayne were shared at some point but I don't remember in which page they are.