My understand is that the character is saying because the actor performs the victory pose with ピシッと決まってて he himself is 痺れた by it?
1 Answer
Yes, the subject of 決まって is 決めポーズ, but the subject of 痺れた is the speaker himself. So an unnecessarily wordy version is 決めポーズはピシッと決まってて俺は痺れたよ.
For the meaning of 痺れる, see the third definition of jisho.org's entry:
- to be excited; to be titillated; to be mesmerized; to be enthralled