And here's a closer look at the top:

Your ID sounds legit but it seems kind of small to cut into. Any pics of the rot? Maybe there's some cure or maybe it's not that bad.

Okay! Thanks for your input. I just couldn't find one that looked close enough to this species so I just wanted to make sure.

And actually this picture was after I cut off the bad parts.The stem was pretty much broken off so I just cut off the gross gooey parts. The rotted parts were turning black and have some white fuzz (mold?) on it. I was too grossed out to remember to take a picture xD Do you think it's too small to make it? My friend was about to throw it out and I wanted to try and save it :o

There is no cephalium starting. Whatever the species, the apical spines are not the beginning of a cephalium. When the plant gets ready to bloom, the effects are not slight, and the spines are white wooly affairs.

Actually if the base is really small it might make it. With most cylindrical cacti the cuttings are usually a bit longer. Yeah I think you're thinking the the Melocactus that has a cephalium. I'm not aware of that growing on other cacti. Maybe there are a few.

CooperDR, there are actually a bunch of genera that make cephalium. Melocactus, as you mention, but Espostoas, Coleocephalocereus, Facheiroa ,many of the Pilosocereus and others make the specialized area we call cephalium.

Thanks for clearing that up. Like I said, I don't know much about cactus! But I absolutely fell in love with how fuzzy and cute this one is and couldn't resist. My Jade and my Hobbit is certainly sick of my hovering.

Here's the picture of the cut I made. I'm hoping it'll callus over properly and not rot anymore. It was already pretty short but I had to shave off about 1-1.5in off.

Did it callus over okay?

Sadly, no. I don't know if it was like what you guys said and it was too small or if the rot had just spread too far but it just started to rot again. Well, it was worth a shot!

I'm sorry for your loss :(