Hinduism: Is the expression of Kundalini best internalized, externalized or both internalized and externalized?

Both. What is internal becomes external too. I have met a couple of people who never claimed to have the energy awakened...but i believe that they were awakened. It was not about spiritual power and energies. It was all about unexplainable and overwhelming compassion. It leaves even nature soaked in the tears of joy.

I'm guessing based on energy work - The most powerful realization is to understand there is no inner or outer - because the two are one and the same they disappear when we realize that we are the inner and the outer because we realize we are all of it - I do not walk in that realization as a constant - yet. But I've experienced it several times... it's very simple and obvious when it is noticed... each remains completely individual... the dance is relative to the characteristic energetic attraction dance of people and things of the one experiencing - bring it all together and all the people and things are you forming the universal expression which you are - all that is attracted to your energy field/spirit is all that you know and see, all that is is in your life - you're completeness.... it is all an expression of you, that includes me typing this.... it could be say that it is all the inner I guess and that their is no outer, that is equally agreeable to me as what I was just saying because it means the same.

The Noticing that everything is me, everything I witness is my characteristic energy dance playing through consciousness, I am God.... that is the highest realization.

Saying that, I tend to either be completely with the inner - or occasionally in the realization above... I never live in the external world - The inner takes priority as in terms of the idea of an inner and an outer - it is my inner which attracts my outer.... to let the attention rest aware of the inner and observing the outer - is a way to realize synchronicity and the absolute Godliness of ourselves.

but as I may have said.... I am guessing it is either inner, or to notice both, or to understand the two that are really the one.

To externalize as far as I know lacks power, it is to become powerless.... (but I may be very wrong with regards the context to which I am answering because I am not very familiar with Kundalini) I will look into it :)

I think, the expression of the awakening of the Kundalini is first experienced by the being internally

and then the being express it externally in numerous psychic ways,

so it is always the both.

well i have no idea what hinduism says about itspecifically consort, but the wee bits and bobs ive picked up from yoga is its about balancing these things, so to me its both, i dont see how it can be internaised or externalised without the other

Haven't you read the packaging? It clearly states 'Not for internal or external consumption'.

It is internalized,operates by body and mind both.

I really don't think it matters either way.