Kind of like how meditation "frees your mind." Maybe meditation (or other more dangerous methods) open your mind to spiritual forces, either light or dark, depending on whom you invite?
I can imagine that is true, though I'm betting the evil forces have to be invited, even if only because you've let down your guard. Q did just tell us: "Humanity is good, but, when we let our guard down we allow darkness to infiltrate and destroy."
And at the same time I don't know that I trust something like "The Christian Truth Center" as a good source, wherein they state:
Masturbation is sex with demons. It defiles and destroys your body, the temple of the Holy Spirit
1 Cor 6:18-19 Flee from sexual immorality. Every other sin a man commits is outside his body, but he who sins sexually sins against his own body. Do you not know that your body is a temple of the Holy Spirit who is in you, whom you have received from God?
Masturbation is about thoughts and imaginations. It’s the result of not casting down imaginations and bringing thoughts to obedience of Christ (2 Cor 10:5)
Satan is able to feed us thoughts and imaginations into our minds when he is not in us – from a distance; a far off. When you entertain his thoughts imaginations and voices, you find yourself doing what he wants, masturbating; sinning.
As you fantasize about his thoughts and imaginations, demons start manipulating your body, making you masturbate – you cannot see them physically with your eyes but they are there.
https://www.christiantruthcenter.com/masturbation-sex-with-demons/
Meditation leads to a tranquil mind, and that is very healing. Meditation is not dangerous unless you're actively looking to enter an altered state with the intention of inviting in evil. That is something very "pro-active." It doesn't just happen because you meditate.