Once Upon A Time In Biology Class

Okay, okay. I get all the questions from the post here, "Why don't use protection, instead?"

Once upon a time in my biology lesson, the teacer taught us about safe sex. Condoms, ligations, you name them...

So...

Teacher : "The weakness of the condom is, might accidentally leak out. Successful chance is only 97%. Which means, 3% of the chances might left the sperms enter the uterus..."

Girl : "Since 1 condom is 97% of success, then why don't use 2 condoms instead? Much safer!"

Boy : "That's why lah, stupid! If use 2 condoms, where got feel?"

Everybody : *LOLFOC*