Much like the act of two men 'playing swords' which is the act of two men peeing in the same toilet at the same time. Swords and Stones refers to the act of two men, one peeing, one pooping, in to the same toilet at the same time.
Brother #1 has to take a poop, brother #2 has to pee, there is only one toilet and neither brother can hold it. The brothers decide to play Swords and Stones.
Flirtgivness is when a person has decided to forgive their ex-girlfriend/boyfriend by subtly flirting with them.
Katie shows her ex-boyfriend 'Dick' a little flirtgiveness (after many moths of anger and regret) by giggling at his lame joke.