Her hands are shaking only a tiny bit. Hell, first time ever touching someone else like this, you'd be nervous too. She pulled from the kiss and tugged Shane's shirt off. "Oh, I like..." Bit her lip before capturing a nipple in her mouth, tracing circles around the other.
She's going mostly of instinct, and things she learned from watching porn. The most she did was give oral to one of her friends, that was already horny enough. So, she'd never properly teased, or done any foreplay whatsoever.