*I am become death, destroyer of worlds.*

Why would someone put a pen in their urethra?

A pen? Foolhardiness.
Using a sterile cylinder of metal or glass is called "sounding" and is a somewhat common fetish. I think this post is a joke, but humanity never fails to disappoint me.
- i saw a video once that used a finger with a long fake fingernail entering a male urethra, that obviously had prior visitors. no idea what the best possible outcome is.
- Glass?
  That sound like a very, very, VERY poor material choice...
Some people find the experience of sticking things in their urethra highly stimulating. Some of those people get tired of the typical thin rod, and need something... More.
I've always been more curious as to who figured this out first. Someone had to be the first to scratch the inside of their dick with a stick to awaken a whole new itch, and I find that just slightly terrifying.
- Sounder here. It started as experimenting as a child. Once i found out that i can make good feeling by touching my pp, I tried everything I could think of to make different good feelings.
  Started with lego spears and antennae around 10 I think. Also tried those little ball chains that are used as pull switches for ceiling lights. They were less fun. Nowadays I use proper surgical grade tools.
  I've got a pencil dick so the biggest I can fit is 7.5mm even after sounding for 20 years. Some guys can take up to 12 or 13 mm and it legitimately makes me jealous.
- are they resonating the thing to make it vibrate? are there some awesome frequencies? otherwise i dont understand the 'sounding' name.
It's cause the other holes are full.
Alfred Charles Kinsey, of Kinsey Reports fame, was into sounding and at least once put a toothbrush up his own urethra... with the coarse end first.

God won't forgive me for having this knowledge

Then we will walk backwards into hell together, with heavy hearts and four middle fingers held high
- I wanna come too! Please pleaseeee
The Allfather encourages the collection of all knowledge, I am going to get stabbed with Gungnir if I spread this information to any but my fose though. Magic may be restricted to women and those who have experienced womanhood but I can still inflict psychic damage!

Sounds about right.

WTF is a "cow vtuber"?

A vtuber who's a cow.
Considering the comment, I think I'm better off not knowing.
https://questionablecontent.net/view.php?comic=4490
since i can't explain, go to urban dictionary.
- this is the closest thing I found
  cow vagina
  when you translate it to Japanese it meas fucking awesome to them.
  Wow that roller coaster was cow vagina!
  +5 upvotes -5 downvotes
  can you link the result you're referencing or put in spoilers?
- I'm not seeing it there on any of the three pages (nor ctrl+f for 'animal' on the first at least)

Skill issue. Should be doing both at the same time.

I'm not going to yick someone's yum, but goddamn I gotta say that's some impressive training. I assume that taking a piss looks like turning on a garden hose.

Probably one with a literal kink in it. The stretched out area will slow the flow vs the un-disturbed smaller diameter. Probably dribble a lot, too.

I also have a Huion graphic tablet, and this makes me not want to use it now. Like it's somehow contaminated with urethra.

Did you buy it used?
- I buy all my sounding gear used. I don't wash it either. Just lick it and wipe it on my shirt.