"NSFW" life/still sketching practices?

[WolfHunner]

Hey, I'm not sure if I should of posted this here or in the adult section but anyway,
I use life drawing tools like QuickPoses.com to exercise my skills in proportion, quickness and perspective drawing. However as you can see the pics used on this site are solo models posing and no two person interactions. I wanna draw 2 or more people having sexual interaction.
I was wondering if any of you have some sort of practices or tools you like to do/use when it comes to drawing sex/erotic/hentai, etc images. Got something?

[Biomass]

I assume you already considered the obvious option. On the internet, pictures of what you seek are not exactly hard to come by.

If you're looking for a way to get very specific poses, I only know about Poser and Daz3D, and I don't like either of those two options.

There's always the hardware solution, buy two art dummies or action figures of your choice and pose them as you like.

If you have open-minded friends , you can have them pose for reference photos. (its not like they actually have to be having sex or be nude).

Go to www.shutterstock.com or any other stock photo site and look up sex, there is some useable stuff there.

[existentia]

There's also MakeHuman, which is free/open-source.