Teething 4 month old

I need help on some kind of teether or anything my son can chew on to help him teething. He had a hard time fitting most of them in his little mouth, and he doesn’t know how to hold it in his mouth yet, he more so tries to push it down. Like he would with pushing his fist into his mouth to chew on. I have several different ones and he hasn’t quite figured them out yet. He mostly chews on his fist/arm or his bib. If he has a blanket near him he’ll grab and chew on it. My husbands great aunt suggested a damp rag but he won’t hold it in his mouth. Which makes no since cause he chews on blankets. lol