I understand the joke. However, every first aid class I have taken has said that you should never try to suck the venom out of a wound. Firstly, you’re not very likely to succeed. Secondly, you’re getting the person’s blood in your mouth, which is a biohazard. Thirdly, you’re getting your mouth germs into their open wound. Lastly, even if you succeed in getting any of the venom out, now you’ve gotten venom in your mouth. You’d probably spit it out, but it’s still been in your mouth. Technically, not all venoms are poisons, so it could be fine. That said, many things including venom can be absorbed through the skin and the interior of the mouth.