Ermigerd that definition tho
This is Urban dictionaries (at least the one I found anyway XD):
"An onomatopoeia often used in manga for when someone with large breasts walks up to (or past) a male character. "
Hahahahahahha xD The one I found was shocking at best. xD
I found
"When your a with a woman in a confined space, usually after a couple drinks and she rejects your offer of sex. In a last ditch attempt, you take your index finger and proceed to stick it in her ass, lightly yelling "Ba-Dump!" in the process. Results may vary.
Kim: you know we're not going any futher right?
Joe: Are you sure.....Ba-dump!
Kim: get out."
Ahahahahahhahahahahhahah
Im gonna add a tag for this (●'◡'●)ﾉ
Hiriki asked, 'What is this badump?'
Otaku dictionary answered: 'In the manga and anime world, it is the indication that the person's going to fall in love to the other one no matter what, where, when, or how it happens.'
Normal people's dictionary answered: 'It's the sound of your heart beating louder than usual to the point that you can hear it.'
Urban Dictionary answered: 'Censored censored censored...' (Please search it at your own risk.)
xD