why do nepalis in nepal talk like that...?

so im tryna get my 3rd generation nepali niece to listen to nepali songs because she asked me to introduce her to some gems. anyway, she found a song on youtube (linked) and she can't get past the title lmao she keeps laughing at the vag part. i was wondering why did yall switch to writing words with 'bh' to 'v'?

https://www.youtube.com/watch?v=RR63sqXQjL4&ab_channel=BudhaSubbaDigital

ps. now i can't unsee bhag as vag lmao