Covered my daughter's mouth

I’ve done this recently with my 3 year old🙈 sometimes she’s just screaming at me continuously when I know she can tell me perfectly well what’s wrong or what she wants and a gentle hand to her mouth to muffle it for a second calms both of us down and she snaps out of it immediately and comes back to earth 😅 it felt odd to do but when it’s genuinely hurting my ears and we’re not making any progress to calm down it worked. Not something I’d make a habit of but I’ve done it 2, maybe 3 times in the last couple months when it’s been necessary!
I wouldn’t trust her or any 3 year old alone around a baby in general though so I don’t think I’d do that regardless of the hand over mouth thing, if baby is content in one spot I’d just ask 3yo to come with me to the loo or whatever (easier than holding baby trying to do things), so they’re not left alone together

Give yourself grace. I think alot of us would have had a similar reaction to that situation. Its ok to tell your child mommy was wrong to do that, apologize, and explain that if she does that to baby it could hurt them. You are not a bad mom. But mom guilt is real. We all have it.

My oldest was the same with the shower when we first introduced it, we brought bath toys into the shower so she could play if she wanted to, and other than getting her clean, we let her choose how much interaction she had with the water. She struggles with transitions so we would set the water running first so she could anticipate it, then I strip down before stripping her so she’s following by example, I then hold her so she can put her hand in the water first and get used to it. If she wants to be held I keep holding her, if she wants to play on the ground I clean her while she plays. It didn’t take long for her to get used to it but she still doesn’t like to put her head under, but she doesn’t scream anymore unless she’s in a bad mood generally. Hope this helps!