adam already sold our souls. all we are left with is try to recieve 'remission/absolution'. on the other side of the medal we also have the option to take it to the other side delibarete rejection of God. so, really, anything where you reject God is kind of 'selling' your soul.
take it as being in debt. you can either do what you can to minimize this debt or try and be worthy of being 'freed' of this debt, or say 'fck it' and increase the debt. like getting yourself into deeper debts. the deeper the debt, the harder it gets. sure you get your new 3DTV, or that new Lincoln or Audi. but at what cost?
if you ask me, personally, i dont really see it as 'selling your soul' to the devil works as if you chant something and you made some deal. I rather see it as you yourself choose a path, and in your mind you make a deal to obligate yourself on taking that course/path/road.
For example, if you would decide to stop smoking, you make a deal with yourself that you will not buy and smoke cigarettes anymore. you then take this path and go for it. did you actually make a deal with yourself? nah, its all in your mind. but you could see it as a 'cheatcode' agreement to make it easier to stay off the stuff.
on the other direction, you could also tell yourself; you know what, i'm going to smoke like crazy and do whatever i can find and go for it. you then smoke like crazy, and since you told yourself you were going to do drugs too, who stops you?
again, i personally do believe Satan and Demons do exist and i really do believe they have supernatural powers, but most of all i rather see humans having the free will to take the path they decide to take. So imho, you dont sell your soul to the devil, you rather decide you go 'that' route. that you won't let morals get in your way. that you'd go on your knees and take some if you think thats the way to go. i do believe one is more or less able to come in contact with evil spirits through opening the mind especially through use of drugs. but i dont think that is actually selling anything, rather it is opening yourself to it.
so in conclusion, if you ask me, you either open yourself to something or you block yourself to something.
the door half-way open is still open. even leaving the door on a small corner open is still open. closed is closed.
locked is locked. if you can't open the door, it's locked. it's that simple. the degrees in which somebody might go to lock their door, rather to prevent it being able to be 'opened' rather easily is another story. putting 20 locks on it, and adding a lead blast door to it that has strong security measurements to it might be 'overkill' but hey, if it works for you.
obviously having the door open a tiny bit will let 'satanical' winds/smell in. so you will get influenced. putting the door open completely, and putting neon-signs around it with full 'welcome mats' around obviously makes it far more easy to 'enter' and accesible.
so this is imho rather what it's like. you dont sell. you just push yourself into engaging deeper into satanism.
"The accumulated filth of all their sex and murder will foam up about their waists and all the whores and politicians will look up and shout ‘Save us!’ And I'll whisper ‘No