In the Philippines, we have a crime called Mutilation. What does mutilation mean? In general, mutilation is the intentional chopping off of a body part which will not grow again. (Please stop with the penis jokes. A penis may grow but not when it's chopped off.) For this crime to be consummated, chopping off another person's Happystick must be intentional or you really have the intent to chop it off. If you just mindlessly played around with a knife and hacked off your friend's Happystick and you weren't planning of even hacking it off, that's not mutilation but Physical injuries.
Let's take a look at what the law says about Mutilation. Art. 262 of the Revised Penal Code provides:
"The penalty of reclusion temporal to reclusion perpetua shall be imposed upon any person who shall intentionally mutilate another by depriving him, either totally or partially, of some essential organ of reproduction.
Any other intentional mutilation shall be punished by prision mayor in its medium and maximum periods."
If you intentionally just want to chop off the tip of your friend's Happystick, that's already mutilation under the first paragraph which comes with a very heavy penalty already. A few inches off the top or the entire penis is intentionally chopped off doesn't matter, the penalty is the same.
Now, if you planned to cut off some other body part, such as an offending finger, that's still mutilation but under the second paragraph.
In short, whether you just nipped the tip, or totally chopped it off, the penalty is higher if such member is used for reproduction, otherwise, if said body part is not used for reproduction (do not tell me a finger used for reproduction, I'll chop off your fingers), the penalty is lesser. The important element is that you have the intention to really chop off that body part.
In the next few days, I'll write about this particular law in relation to RA 9262 (Anti Violence Against Women and their Children Law) on women chopping off their partner's Happysticks and Battered Woman Syndrome.