I know what I feel when I feel it but I don't always know why I feel it. That takes time to figure out and it usually happens over a period of time having the same recurring emotions given the same person/issue, etc. If I do take time to understand why I feel a certain way sometimes it feels like a dirty secret I'm keeping. Sometimes telling someone else feels like I'm betraying my own trust. (weird. I know) So. I guess this would be guarded.
This is EXACTLY what happens to me (though I don't think I would have ever been able to articulate it as well). I'm finally starting to understand why I felt so suffocated when I was surrounded by women who constantly shared their feelings and insisted that I do the same. Ugh.
I'm actually trying to think of tips on how to do this on those types that need a lot of verbal affirmation and feedback, because that's probably the toughest for ISTPs. It would help me too, thinking of some ways to fill that (because its a huge ENFJ need) without it being too forced. I know the ISTPs I know are careful what they say and have a sense of integrity that can cause difficulty in using words that might come off as mushy, dramatic or fake. I imagine if one isn't used to language of the unconscious a lot of it comes out sounding like forced poetry, and can make the ISTP feel ridiculous, inconsistent or vulnerable in a way they don't want to be. Also, like MDP2525 said, I think a lot of ISTPs might think that their feelings on a subject are already 'out there' & that putting extra words into describing or projecting them is either overkill or attention grabbing.
I really struggled with this when planning my wedding. I spent *weeks* trying to find exactly the right words to express my emotions both for our wedding invitations and the ceremony wording without sounding mushy or overly poetic. It was exhausting. I am so relieved that the wedding is over and I don't have to deal with all of the emotional expression aspects of wedding planning anymore.
I am terrible at validating other people's feelings, particularly when they are emotionally needy. It's really backwards in a way. If someone needs someone else to tell them how great they are because their self-esteem depends on it, I will deliberately avoid giving them this feedback. I don't like feeling responsible for other people's happiness (or lack thereof).
I also think complimenting or giving verbal affirmation of any kind might be awkward because of the processing time it takes for an ISTP to decide it's worth it and genuine. Like MDP2525 has said, (and I've heard other ISTPs say something similar), by the time the expressions might be seen as genuine or worth saying, they seem out of place or no longer appropriate for the time / worth saying. If an ISTP could make attempts to recall thoughts of what could be genuinely validating if expressed, just as they might remember an act of service (like, "I should fix the ... later. X would like that."), they could limit the awkwardness of expressing it later by saying "I was thinking about ... (and then express the validation) today."
I can't even count the number of times I have chosen to say nothing because by the time I figured out the "right" thing to say I felt like too much time had elapsed for it to still be worth it...
Another type of validating (like in the post you mentioned that I commented on) another person is through quality one-on-one time. I think ISTPs are naturally not tuned to need a lot of this from their relationships or understand what it really means without a bit of wonder. ISTPs are action oriented and seem to value people as extensions or additions to the activities in their life. They also get comfortable with people and feel more relaxed in their presence, but the other person does not necessarily have to be in the spotlight or a part of the action.
This is definitely true for me. My husband and I can spend an entire day sitting on the couch, each working on our computers without saying a word to each other, and feel like we got a lot of quality "together" time at the end of the day.
Are ISTPs good with physical touch? I get a lot of mixed information on this. I know some people find physical touch validating. To some it is the primary expression used to gauge feelings. I think, for me it is about 3rd on my list but quite necessary for romantic relationships. I've heard ISTPs can be very cuddly (mine had Aspergers so he wasn't for reasons other than type) and that ISTP dad's can be really physically loving to kids. But I've also heard that touch is similar to words and can be guarded against if it exposes to much or causes vulnerability.
It depends on who is doing the touching. In my marriage, physical touch is probably my primary method of expressing love to my husband. Snuggling on the couch or holding hands can be much more gratifying and meaningful than trying to express my feelings verbally. In my close relationships I give hugs freely and frequently.
On the flip side, I am extremely uncomfortable with physical touch when it is initiated by someone that I am not very close to (particularly when it is unexpected, or more intimate than I am comfortable with, e.g. a back-rub from any man other than my husband, or someone reaching over to rub my shoulder to try to "comfort" me when I wasn't in need of comfort). In those situations I feel intensely claustrophobic and look for any excuse to get as far away as possible. Close talkers (people who lean in no matter how far back you lean in response) make me feel the same way.
To not be trapped by feelings or to not use feelings to judge.
