Everything varies. But the general consensus is that a part of a yukkuri that's completely removed or heavily damaged can't be regenerated (even with orange juice, in cases).
Mister, good morning eajy! Even though you're Alice's mister it looks like you're doing snore-snore. That's not city-sect Yu? Mister, what is thiis? It looks just like mister peni-peni ...Alice's mister peni-peni?
I'm of the mind that multipeni are "extensions" and the ability is disabled if the "real"one is removed.
Mishter, good morning eajy! Guesh Awishe went to shweep-shweep even though Mishter waj awound--that wajn't vewy shity-shect!
Yu? Mishter, what'sh thish? It wooksh jusht wike a mishter penipeni!
...Awishe'j mishter penipeni?