Rare animals also exists. I do believe that very shy ESTP could exist, but, honestly, I never met one.I know someone who was typed as ESTP, but he is quite shy and sometimes even stutters slightly when he speaks. Is it possible he was mistyped?
Sometimes hapens that ESTPs arent much talkative, because are around introvert(s), dont feel comfortable in their skin (not much of pretenders)
have interest in you and dont know how to say. But this version comes more with the guys (atypical, by the way), girls dont tend to loose it that much in case pheromones are in the air. Is it possible that only person he is shy with is you?
I play it down with many introverts myself, because Im strong E and I dont want to disturb. My impression with many introverts is that they need long time to adapt to new people, so I give them this time. Costs a bit of effort.