stirring her borscht
Having vaginal sex with one's girlfriend/wife/fuckpuppet while on her period. Especially relevant if your female sex partner is a Germanic/Slavic minx.
"So how was your night?"
"Not bad. Genevieve was on her period, but I still got to stirring her borscht, bro-man-dude."
"Not bad. Genevieve was on her period, but I still got to stirring her borscht, bro-man-dude."