I couldn't do that to her. After all, she is my step sis who can take care of herself and knows what is good for her and what is not. If there was any other girl in her place, I would join Nala without hesitation. But I won't touch my own sister here in front of him. So I stayed away from them and just watched their wrestling. At one point, he grabbed the top of her t-shirt and managed to reveal Nala's big breasts with pink erect nipples. She seemed angry and covered her breasts again. She tripped his legs and held him underwater for almost a minute. When she finally released him, his face was completely red and he could catch his breath.