Most slashlovers like this couple the best: Sirius x Remus. In their schooldays. Enjoy it.
Little story about the Yule Ball in their fourth year. Doesn't contain a slashrelationship, but does contain a slashcrush. Enjoy it.
Another SLASH from my side: but this one isn't that physical, more phsylogical. James x Sirius. Enjoy it.
SLASH! Ron Seamus, don't read it if you can't stand boytoboy scenes or when you're younger than 12. Enjoy it!