Daniel (Hypnotic Dreams' author) wrote in his inraptured.com profile that he loves 3 things in femdom recordings: 1) where a hypnodomme covertly sneaks hypnotic commands into your subconscious to make you get hard on command, then 2) she tries to persuade you that being erect is the same as being hypnotized, and 3) when she keeps you hard and uses some kind of sexual tease and denial to persuade you to accept further hypnotic suggestions. such as your cock is her obedient slave.
Held, and Manipulations are intended to be fantasies of hypno dommes covertly seducing you into a trance, and then covertly seducing you into giving her total control over your body's sexual responses.
In Held, part of that seduction is the sugestion that your cock automatically responds to the domme's overpowering hypnotic sexuality and there is nothing you can do about it. Your cock will swell with overhelming desire, and put you into a trance so the domme can manipulate your mind while she teases your cock. So the trigger is that when you see beautiful cleavage, you'll imagine the woman holding your cock between her breasts and that image in your mind will trigger an instant erection.and an instant trance, making you vulnerable to more hypnotic suggestions.
I don't know if Daniel actually intended to make this file addictive. ,But in th story he said inspired him ( http://www.mcstories.com/Bianca/Bianca1.html ), the hypnodomme does make her subject addicted to her, and that's part of being seduced into her control.
In Manipulations, the suggestions for craving the hypnodomme's sexual control are clearly deliberate. There's a suggestion in the middle of the script, that whenver you feel your cock stirring, you'll remember that it only her hypnotic control can make it fully erect. You'll want to hear her voice, and the instant you hear it, you'll go into a trance, become fully erect, and get lost in the pleasure while she manipulates your subconscious. I listened to Shibby on Discord when she recorded Manipulations, and it's intensely erotic.
In The Couch Trip, the hypnodomme conditions you to become erect on command, and the trigger phrase can be used by any woman. It's not nearly as covert, but if you're in D/s relationship, you can give your domme the command and she can trigger your hard on.
Tammy used to do Niteflirt sessions - I don't know if she still does. Shibby does group sessions on discord, and offers audios on Patreon. But As far as I know, niether accept online slaves. So the 'addiction' is just part of the fantasy.