The're in the waragon cave. Had to kill at least 40 of them before I got the knowledge.

I've killed well over a hundred of these things and finally got it when I was about to give up...
I've scouted out the area and found 5 spawns for em. One of them is along a pathway heading into the center with the huge beast. The other 4 are kind of close together in the bigger area with a rock sitting in the middle (along pathways leading into room). Linked a screenshot of the room I'm talking about.

Remember you can also gain knowledge by gathering from the corpse. Helped me

Only noticed 1 spawn point for these guys...gonna take a while =(

hier hab ich das wissen erlangt

4 of them are in a line close to each other. Keep killing those Bastards. I spend 3 hours in this wet dark cave killing worms.

I did grind there like 2hours and nothing... I hate it T_T....
Will come back later again :/

Me he metido en la Cueva de los Waragon para conseguir Líquido pehajoso con jeringa y lo único que consigo es sangre de gusano. He estado casi dos horas y no he conseguido líquido pegasoso. Así que... vosotros mismos.