It's almost certainly a tick, and suffocating it is a good way to get it to let go without doing any damage to the snake (obviously don't squeeze too tightly). In addition to alcohol, petroleum jelly makes a good agent of suffocation, but don't use both at the same time. Once the tick has let go, you're free to kill it in any way you see fit, including burning with a match head, pinning to your corkboard and letting it starve, dropping it in a nearby spiderweb, or zipping it in a baggie and dropping it off at the vet's office.