Just a drive-by rec here of something in that good old "squabbling for dominance begets sexual tension" vein of Snack:
Cleaning by
augustusPairing/Characters: Severus/Sirius
Rating: Teen
Words: 1255
Author's summary: Sirius and Severus argue. Set during OotP.
Author's warnings: none
Quote:'Because you're obsessed.' Severus's voice rose, his own eyes seeming to become even blacker as he spoke. 'Everyone knew about the two of you at school, you know. There's no point in pretending your feelings towards that child are fatherly ones.'
'You really are a foul, pathetic man,' Sirius sneered. 'You haven't changed at all in the last twenty years, have you? You're completely unable to believe in anything good or innocent.'
'Not when it involves you.'