I may feel clingy inside, but when I do, I withdraw from the other person. I guess I do that to make sure they still want me around, and I'm not really being clingy in a way that affects them.
Basically, I might feel like being clingy, might even on occasion feel desperate, but I will not allow myself to impose on another person that way because I think it's wrong. (because it imposes on them / inhibits their freedom / dominates them in some way, rather than giving them freedom to choose and respond). I will never allow myself to be a burden. Thus, I just pretend like I'm fine and suffer alone.
This is exactly what I do when I'm feeling clingy.
I may be totally obsessed about the other person, think about them 24/7, and feel like controlling their life so they could spend more time with me... but the more I feel like this, the more effort I'll put into hiding these feelings. I'll just suffer alone.
This is because I can't stand clingy people myself. I want - no,
need - my personal space, independence and freedom, and the best way to make me run away is becoming clingy or needy. Therefore, I avoid doing it myself.
Of course, I've overdone this behavior. As a result, I've sometimes appeared uninterested or unattainable while I've been in fact totally obsessed with the other person, but I don't mind. The most significant, meaningful and compatible relationships in my life have resulted precisely because of my non-clingy behavior! The people most compatible with me (fellow NTs, actually) have stated they were attracted to my independence and non-clingy behavior because they'd had bad experiences with clingy people themselves.