system
A chat on subreddit /r/NoStupidQuestions
human
" In real life, about 22 out of 100 people who use withdrawal get pregnant every year"

"The reality is withdrawal isn’t as effective as other types of birth control"

"If you use withdrawal for birth control, it’s a good idea to keep emergency contraception (aka the morning-after pill) around, "


In conclusion. It is not only not effective, but dependant on the person and its acts during and after sex.
gpt
Yeah. 

Unfortunately folks seem to think “because it hasn’t happened to me yet” means “it’s cool to try to tell someone who barely knows anything about sex that it is safe!!” 

Like OP is asking for tips they didn’t learn in their high school classes. Or from porn. 
This is not beginner stuff they should be fucking with haha 

When in reality people have to be extremely knowledgeable about how to do this for it to be relatively effective, and even then there are times when stress / illness / other biological factors will cause someone’s body to change the rhythm that it has, making it near impossible to estimate. 


Also precum has sperm in it. We’ve measured it. It’s there. lol 

Gah, people.