Word of advice. If you DO take a thumbprint, do it with a group of people that love you and know what you are doing in advance, because they will likely have to babysit you.
Best to be away from public, but not so far that you cant get help if needed.
You're very unlikely stumble upon crystal LSD. Generally speaking you need to be somewhat involved with distribution or at least know high level distributors. You might stumble on someone who'd be willing to share, but often in these stranger encounters the person will dose you because you asked and then they kinda want to see what will happen without having to support you so I again encourage you to read my 1st piece of advice. It's not too difficult to end up in jail, hospital, or worse without a support system.
In fact, you can't casually print yourself at home thinking it's going to be ok. You will probably get naked, you will probably think you're dying, you will probably leave your house naked looking for help. At least I did, and from what I've heard, it isnt very uncommon in these types of experiences.
Here is my AL-LAD thumbprint TR:
An Experience with AL-LAD. 'The Thumbprint' by Didgital
erowid.org