Do you shower together with your boy? Do you think there is negative impact to shower with mummy?

I don't think there's any negative impact on the child to shower with any parent. I showered with my son till age 4. Teaching him the right and thorough way to clean himself was important till then. Now he's a big boy and showers with his younger brother - and they love it! I think as long as you are comfy with it, it's fine. When he's older and is independent to clean himself well, then you can let him do it on his own.