What is Bountiful?

"Please keep sitting on my lap," repeated Xie Yuansheng as Feng Xinying stared at him. She was laughing inside but she made a poker face on the out. 

She fluttered her eyes and said, "What is a member?" 

The look on her face was so innocent that Xie Yuansheng didn't know how to reply to her. He kept quiet and in fact just so that he wouldn't blurt any nonsense in his intoxicated state, he even pursed his lips. 

She urged him again, shifting a little in his lap, "What is a member and how will it burst?" 

Xie Yuansheng shook his head and made a sound, "gnmmm". 

Feng Xinying frowned. "Hmm?"

He hung his head low and rested them on her hands. How could he answer her? His mind was not thinking straight. He just held her tightly and waited for the journey to end but for the rest of the journey Feng Xinying kept on teasing him by either moving in his lap or asking him every lewd question she could think of about member.