Its pretty effective IF AND ONLY IF he actually puked out before starting to ejaculate. Sometimes men don't realize they are until too late :)
Thats how I got pregnant with my oldest son..it didn't happen the first time though. Now I have an amazing 9 year old boy :-)
Quoting A Beautiful Disaster:" you gotta have a lot of trust in the guy, that the pull out fast enough. I think the ones getting pregnant are not doing it the right way, sorry to say. "
he would jack himself off to make sure he pulled out in time. i think it was just timing with ovulation being a little different.