Just don't let him into the bathroom when you are having a bath. My RB Aby Zoe used to join me in the bathtub. She would step on the bits of me that weren't deep in the water, my stomach, my chest etc. She would sit half immersed in the water and swat at the bubbles. Or she would sit on the edge of the tub and swat at the bubbles. I had to let her in or she would wail outside the door and try pushing it open. Maya and Bodhi are NOT allowed in as it is my quiet time and they already spend enough time in the sinks and bathtub when I'm not there.