If you want bufotenin that badly get yopo seeds. A. Peregrina has mostly bufotenine in it's seeds.. And the extraction is very simple..
Dmt is so common in so many plants such as ice plant and that's all over. Just don't make ice plant tea.. I can only imagine it's like drinking the thickest cacti tea ever. And you would probably puke it out beforehand lol this plant is obviously telling us there are better sources of dmt.
Edit- wow I didn't even answer your question. My apologies haha.
You just have to squeeze their venom glands. They are pretty noticable, but I would leave the little guy to do it naturally in defense not because someone wants an experience.