Trying to edit a model to give it a butt

I’m still extremely noobish at Blender. I just figured out texturing yesterday and now I’m trying to focus on one of the things I want to do, which is give some models a butt. …Butt I’m not sure how I would go about doing it. If anyone has a discord and would like to add me so we can screenshare/chat, feel free. My discord is Sonario648#7356. Screensharing would allow you to see what I’m doing, and you can also guide me better.

It’s just two lumps separated by a crack (a ‘crease’ in blender terminology).

Butts are easy. You got this.