I put ds1(nearly 4) and ds2 (22 months) in the bath, wash their hair etc. Then I clean the bathroom while they are playing.
Then I get in the bath with them, let some of the water out and stand under the shower bit.
Once I've showered, I take ds2 out, keep the bathroom door open, leaving ds1 to play under the shower.
I sit on the landing with ds2, with ds1 in sight as I'm sat next to the open bathroom door, and I dry mine and ds2's hair while he plays with some toys.
Once me and ds2 are ready, I get ds1 out of the bath and dry his hair.
I have a stairgate at the top of the stairs and high locks on all the bedroom doors, so the landing is completely safe.
This is the only way I manage to stay clean! I've tried having a bath or shower at night but ds1 is a light sleeper and he always wakes up.