Farting in a tuba while she was burping from having eaten cake before despite being a ghost was allowing Melody to embrace her smelly side of being a ghastly gassy girl since the stinker was quite bloated and her growling stomach was letting her produce such bassy brown notes that shook the entire room while she playfully fanned the rotten air. "Peeyew~! Now these scents are gonna stick to the entire room! Good thing that I can always make room for more good stuff...!"
Evidentially she continued doing this for enough time until finally Melody decided to briefly make herself into a more solid form since she wanted to make use of being in the toilet where her tuba toots carried over; of course her poltergeist poots didn't sound anywhere as loud due to the toilet bowl muffling them but it was all relieving all the same.
"Now this is quite the reliever! I bet there's more things I can fit my fat farter into...~"