Do you think it’s true that intp’s are generally lanky, and round shouldered with flat cheekbones? I read that somewhere and was surprised how well it fit me but it seems so specific. Since you type using physicality, I thought I’d ask.

The visual typing thing is socionics, I think.  I am using muscle tension, which can be similar but is a little different.

I don’t think that every person in a type ends up with the same kind of body, or silhouette, although occasionally similarities do crop up (and certainly some INTPs look as you’ve described).  I do think that if you have two people from the same type performing the same activity, they are likely to use their muscles in the same way to accomplish that activity. 

In this way, I think expressions and movements tend to be more similar across type than physical features.

Since ENTP’s are considered the most introverted of the extroverts, what would you suggest for people struggling to tell if they’re an INTP or an ENTP? What difference do you notice?

I do not buy that any one extravert type is the most introverted.  I think there are more and less introverted people in every type.

Same advice as to the last question from the ENFP anon.  Find an ENTP and an INTP in conversation and figure out which one you relate to more.  (David Schwimmer and Matthew Perry?)

My tags might be a bit of a mess (haven’t gone through the INTP tag in a while so there may still be some ENTPs and ISTPs in there, unfortunately).

I usually find that ENTPs are way more openly socially anxious.  INTPs are generally more likely to try not to draw attention to their insecurities, partly by just talking less. 

Of course, there’s always some crossover, so grain of salt, I guess.

My boyfriend keeps insisting he’s an INTP and even took a test to show me. But in my opinion he acts way more like an ENTP. He claims to be an introvert because of his social anxiety but I see a huge difference in his social behavior anyways compared to our INTP friends. Plus I tried explaining even though I’m an ENFP I tend to be very unsociable and shy. How do we know for sure what his mbti type is?

No way to know for sure, I guess, but see if you can find some ENTPs and INTPs together in the same show/interview.  Which is he most like?