flush over

To 'Flush Over' someone is to flush the toilet whilst they are speaking, effectively drowning out what they were trying to say to you.

Stef: 'What did you think of that exam?' (whilst competing with sound of toilet flush)
Rachel: 'Oh Sorry I just Flushed Over you. You are going to have to repeat that'
Stef: 'Wow that really was one hell of a Flush Over, I am actually mildly offended!'