Unfortunately for Peter, he's distracted by his own shaking just long enough that Tony has enough time to grab and pin his hand.

Peter's initial instinct is to try and yank his hand away again. He knows what's coming and he doesn't want any part of that, but now if he were to do that he could accidentally hurt Tony and he really doesn't want to do that.

"No. Nonononono, Please Mr Stark, you know how I feel about needles and there's noting to numb the pain and even if there was it probably wouldn't work 'cause I'd just metabolize it-and oh my god this is gonna suck." He spits out faster than anyone should ever be able to talk.