Everyone knows about Wailord and Skitty, being bred through the Field Group, but its time to enlighten you to a far more sinister comparison.

Wailord is 47'7" in length
Comparatively, is is about the length of a Gray Whale
Gray Whales have a penis of about 6'0".
Even if we assumed that it had the gift of Blue Whale genetics, that still maxes it out at around 10'0"
Meaning Wailord's dick is 21% of its overall body length
Still in comparison with Skitty this means Wailord's dick is 500% the size of Skitty, or 5 times Skitty's size
A larger comparison is Diglet
Wailord's dick is 1500% the size of Diglet, or 15 times its size

But Barbaracle is a barnacle
Barnacles have dicks that are 50 times the size of its body
With Barbaracle being 4'3" that means Barbaracle's dick is 212'6"
It also outstrips Wailord in sheer size
To make matter's worse, there is Shellder
Now Shellder is in the same egg group as Barbaracle
Barbaracle's dick is 21250% the size of Shellder
That is Barbaracle's dick is 212.5 times the size of Shellder

Enjoy the eldritch reality of that sex.