G.H.
Did you try sitting yourself in the big tub with small amount of water and her soap with her on your lap. This could be slippery so hubby should lay her on you once you're in the tub and settled. Lay a warm soapy hand towel or small towel on your legs so as not to be to slippery while you're handeling her. Take all the precautions you can to being a responsible mama; i'm sure you will. If she's facing you on your legs you can talk and sing and entertain her thru the bath. Call hubby when she's ready to come out. You'll probably want a bath yourself after that.