Casually looking down at your legs to make sure no blood leaked through your undies while you're on your period.
And then getting caught doing it

Me: *glances down*
Person: *staring*
Me: ...uh oh
Person: Uhh...
Me: *coughs awkwardly*
Person: Are you...
Me: SHAMOZZLE *throws glitter at person*
Person: GAH
Me: AHAHAHA *runs away*