When you IWT, you can press the key or you can spam it.

If you press it, and wait...
Your toons move towards the target and then stop.
If the target moves again, press it once and they adjust.

In PvP, you pretty much have to spam, as your opponent generally moves about constantly.

If your toon is in melee range already, pressing IWT is not going to do anything whether you press it once or spam it like crazy.
If your toon is not in melee and you spam it, you generally get the chicken with the head cut off effect... which in PvP is highly beneficial.

Basically decide if you want to selectively press it.
Or if you want to spam it.

If you opt for spamming it, you will get run away toons and can use these options to recover:
- Broadcast a slave only movement key, which will end their movement.
- IWT to a different target, which can include a lootable corpse.
- Press your Follow key quickly, while they're all still in range of the target.

You can also enable Strobe in Jamba, and set it to Strobe after combat ends.
I personally detest the Strobe, but some people like it... and it is another option.