A lot of the signs and external sensations, like that tugging feeling, are going to be unique. There are physical signs of them thinking of you that feel like a tugging feeling for some people. So there probably are signs you will feel if they’re trying to manifest you, but it’s probably closer to the signs your twin flame is healing, and it will be specific to you and your path to union.
This might well be a sign that they’re trying to attract you, but it could just be that they’re becoming more spiritually open (still a great sign), but not that they’re intentionally trying to use a manifestation technique specifically with you in mind. Just trying to balance expectations here.
They could be unconsciously trying to manifest you, it really depends on where your twin is on their own journey. The more intentional it is, the more I would expect you to see external synchronicities like multiple repeating number patterns. A simple feeling of ‘tugging’ could mean all sorts of things.
They might be using visualization or focusing their thoughts and energy on creating that connection with you, sometimes without even realizing it. The tugging you’re feeling, especially upon waking, could be that telepathic link being activated. I’d pay attention to any dreams you’re having. Shared dreams are a thing and could be another sign they’re reaching out energetically.