Ooohh u r very cruel my tits r all red n blue after this thanx very much

Welcome to gD big girl...
Tie your tits tight at the base. After 20 mins use the vacuum cleaner hose to create four circular bruises on your aching swollen tit meat. 5 mins per circle should do nicely.
Dont let the vacuum overheat! Once done you might try inflicting carpet burns as well by either pulling or pushing your poor tortured tit meat face down over the roughest floor covering you have...