Have had to deal with this question myself, grew up in churches that were very straightfaced and straightlaced (Methodist, Presbyterian, Baptist styles) and after my parents split up, got to know pentacostal and catholic congregations.
Dad's search throughout my childhood was for that fellowship, warmth, and the presence of the Holy Spirit that he experienced in bible study in college.
What does the presence of the Holy Spirit look like...?
It does not have the guise of the kundalini teachings and yoga goals. The original material and traditions from eastern religions has a basic assumption- that man is a self-actualized (independant and not interconnected) spiritual being, a godling seed, and that life is about perfecting that seed. It has a teaching about a power that can be called God, but it does not teach God as a family member.
Chrisianity teaches yes, that the human being is a seed of God, a being with a spiritual component that survives after death, and yes, that life involves perfecting ... *
Repentance can be compared with parasite cleansing, TBH, it sure gets rid of a lot of unwanted baggage on the side.
... What does the real thing with the Holy Spirit look like-?
Restoration of the deep, inner relationship with God the Father. A healing from the inside out, of old pains and traumas that hit first the soul, and which later became manifest in the personality and body.
It's 'My father and I', 'Jesus before me,' 'the Holy Spirit in me', and not 'I do this through my meditation'.
The power source is different. The ability to work miracles and change reality is built into the nature of who we are as children of God, but like an unused muscle from birth because of the power drain of sin.
Yoga and Kundalini hijack that wiring to allow fallen spirits to coinhabitate with humans, but it's not a spirit to invite in. Jesus spent his time of ministry here casting those types out.
Miracles worked from the Holy Spirit are for the glory of God and revealing the Kingdom- where willing adoptees, Children of God (Hebrew, b'nai elohim) belong.
Uhm, the question of parasites as physical embodiments of demons..
Not really. Book of Jubilees (part of the canon of scripture in Jesus' day) explains that creatures started eating eachother in the day of Genesis 6: 4-7, when an original team of b'nai elohim (angels from God who were given bodies to try and teach men the way of salvation) chose to reproduce with women. They preyed upon (parasitized) humankind, and they had a portion of spiritual authority from God when they were set to their work.
Parasitisim seems to have become a part of the natural world right at that period. Biological minutiae like tapeworms, protazoa, etc would have been passed from one creature to another by meat-eating, and had to adapt to survive at that point.
The defenition of Demon is found in Jubilees, as the remaining spirits of the nephilim who were wiped out by the flood- a tenth fraction of the entire population. They are disembodied spiritual entities, without a resting place (a physical body), without food or peace. They had human aspects, lived lives similar to humans, but now have to deal with an eternal soul, and take out their fate on especially women and children 'as they proceeded forth from these'.
Demons are, from what I have read, spiritual parasites, and really do drive men and women as much as possible towards activities that will get them to accumulate physical parasites.
The Holy Spirit..
Yes, the Holy Spirit uses the power of tongues. Languages were /distributed/ by God at the tower of Babel, and it's a fool's errand to point fingers at fellow believers and cry demonic activity. Scripture is enough documentation about tongues, it's meant for private building up of the spirit (like lifting weights). It's not the fullness, the peace, the shalom of time with Jesus in prayer, it's a method.
Shalom is a place of intimacy with Jesus. It's where one can comfortably live in one's own skin (whatever the internal struggles that are going on) and come to the realm of the Kingdom (God's kingdom of heaven, the spiritual overlap with the physical plane).
It's where Adam and Eve were, when living in the Garden of Eden- they had the holy spirit in them, in communication consistently with their creator. It's where the curse of sin and death has been thrown out the window, and it's what's available right now through Jesus.
I envy people at times when they describe the sensation of peace of mind and heart that they have experienced after a very thorough parasite cleansing. I do not have that yet- just some experiences of passing the bastard bugs on the loo at points.
I don't think that state of mind is one that can be labled Shalom though- I think that is a much richer overlap of God and man- a relationship where there's no sharp corners that create disunity between God's will and our willingness.
TL;DR: Naw, physical parasites are not the thing and the whole of the thing when it comes to demons. Yurs, be careful of yogi/kundalini/asian mysticisim, it makes you the responsibility party for all the work! WTH are demons? Reed the above tekst, O ye of short attention spans. <3