My little man is almost two, and sometimes he falls asleep while latched on at bedtime. That's fine. Problem is that he has teeth. Sharp ones. When he's awake he remembers not to bite, but as he falls asleep all bets are off. When I try to stick my finger in to protect myself and break the suction, he has sharp teeth in the back too. Ouch! (used to be just gums back there) So... how do you defend yourself from the chompers without waking the sleeping toddler??
Before my toddler is totally asleep but after he is well asleep (sorry if that is confusing) I pull my nip out of his mouth and kinda hold my finger under his bottom lip above his chin for a minute. He moves a bit but falls back asleep.
If I pull it out too early he wakes up and I latch him back on. But I try it again after I think he's asleep enough. It's taken a lot of trial and error but it's totally worth it to not get bit!