When a girl has her period, and is wearing a tampon, you pull the tampon out and stick it in her ass. Then have sex in a position so that the tampon is sticking up in the air so that she looks like the Calgary tower. When you're done, take the tampon out of her ass and reinsert it back into her pussy. You can follow this up with a Dirty Lanny.
My girl pissed me off so we did the Calgary Tower and I finished it off with a Dirty Lanny