Sure, Cassie has the strength of a hundred men. It's part of her powers, part of who she is. She can brawl with the best of them - in this case: Wonder Woman, Superman, Superboy, and the like - and that makes her feel pretty awesome. Who wouldn't want to be one the strongest of the strong? A superhero in the truest sense of the word?
But the blonde heroine can't help but feel a rush of true excitement when she fights one-on-one against one of the Team's resident hand-to-hand experts - none other than the third Robin, Tim Drake (yeah, she'd gotten him to tell her his secret identity, score one for Wonder Girl). Cassie always relies on raw power to win her fights, but when she's up against Tim, she has to use a bit more finesse.
Tim is graceful as a swan - he'd give her a Batman-esque glare if he ever heard her say that - and he has his own sort of strength. He's shorter than she is, but he knows how to use his weight to its best advantage. Sometimes Cassie gets so distracted by his elegance in fighting, and that's when he strikes the hardest. They've sparred a grand total of 14 times so far, and he's won every match. This frustrates her to no end.
So one surprisingly mission-less day, Cassie challenges Tim to another fight. Most of the Team is at the Cave, citing boredom in their normal lives, so they decide to come and watch. Everyone is sure that the normally straight-faced protege of Batman will win - even Wonder Girl is fairly sure of it - so no bets are placed, unlike they usually are. So it's no wonder that everyone is surprised when the match ends after 20 minutes with Tim pinned underneath the taller girl.
They're staring at each other, wide-eyed, and one part of Cassie's brain is cheering. I beat him, I beat him, I beat him! This is an exceedingly special occasion, and she wonders if she can convince Miss Martian to make a cake in celebration. But the rest of her brain is focusing on the dark-haired boy she's sitting on top of. His chest is heaving up and down and sweating beading on his face. Something about having him beneath her makes her hormones go into overdrive. I never noticed how hot he is, Cassie muses, unconsciously licking her lips. The Boy Wonder is looking up at her and she wishes she could take off his domino mask to see how intense his whatever-colored eyes are. The idea is extremely appealing.
She makes a rash decision and tries to peel the mask off. Tim doesn't seem to like that idea very much, so he rolls them over so he's on top. And now he's staring down at her and she's staring up at him and she really wants to know what his eyes look like and oh my god what the hell is he doing? He's dipping his head down, seemingly moving in slow motion, and then their lips touch, and she honestly didn't know how much she wanted this until it happened. And there's fireworks and butterflies and songbirds and she doesn't care how cliche this all sounds because Wonder Girl and Robin are kissing and this was completely unexpected but somehow it all makes sense.
In the background noise, Cassie vaguely hears catcalls and whispering and giggling and the distinct sound of a camera clicking. She's going to have to ask the girls for a copy of the picture later, because hell if she's not going to want to remember this wonderful moment, but that will be much later. Because she's only just discovered that Tim's hair is ridiculously soft and that he's a surprisingly amazing kisser and holy fuck she's going to make the most of every moment of this.