FanOfGoodPics: These dogs know what they are doing.
Keeping Kryptonite close to her, they are making stretching permanent. At the same time, mutagenic properties of its radiation field are causing changes in her reproduction system, making it adaptable to seed of just about any creature.
Kara doesn't know it yet, but she is going to give birth to several litters of pups with mutated Kryptonian gene inside them; allowing them to "spread around" their "love" and species.
Even if she did know about it, she would not care. Ale she cares about, at the moment, is feel of being fucked by dog, and coming again, and again, and again...