Since a teacher of the Chinese language taught us the correct pronunciation of "笫" in high school, I have corrected other people many times.  

“床笫之私”的笫，不是读di吗？搞懂意思就不会读错了！ - 西瓜视频 

PS. Beauty speaks for itself. Ya Xin, the hostee of the video, always presents herself in light make-up, but she is a beauty.