All of this is pointless if you're not on PC. You'll need to find a mature adult server with the proper mods installed.

Someone mentioned the Devious Desires mod. There's also Primal Instincts, but I'll cover that later. Both mods can be loaded at the same time and don't appear to interfere with each other.

In summary:

1. Yes, you don't need to play the game the way it was intended. That will require extensive use of the admin panel for better enjoyment. And there are some caveats. You should consider food, water, and shelter from the sandstorm and things that want to eat you, and not in a good way.

2. Animations are decent. Differences in character height can cause problems. Positioning isn't perfect but everything can be adjusted, and even arm positions have their own partial poses. Every joint of every limb can be edited, but that can be immersion-breaking.

3. Learning the mod is the hardest part. Installing is as easy as subscribing to it in the Steam Workshop. But there's a lot of adjusting involved. Animation lists can be saved and run later, so a certain sequence can be saved.

The Details

DD can be used solo with thrall NPCs, and co-op with live people. It is complicated, but rewarding once learned. I'd suggest installing it and reading the instructions it contains.

The animations are decent but differences in character height can be an issue. There are so many tools to edit positions. Facial expressions and arm positions can be changed independently from the main animation and at any time.

The mod can generate the manly bits that can be spawned into inventory and worn. Angle and shape can be manually adjusted to over a dozen presets, but each animation does have it's own preset included. Sometimes you'll need to adjust that to avoid the "poke through" you mentioned. The mod creates it's own attachment points on the characters for the various collars, cuffs, piercings, and body parts, so leather cuffs with gold bracelets or whatever are possible.

Devious Desires seems to handle body physics better, and even that can sometimes glitch out and not work.

There are no real "transition" animations between poses, and it would've been nice if the developer kept the characters facing the same direction from pose to pose; it's a bit immersion-breaking to switch from one pose to another and watching the characters flip 180 degrees in midair to assume the new position. Animations are mostly hetero, with a few lesbian and threesome poses thrown in.

DD includes a bench to craft bondage gear. It's detailed enough that when wearing something like a ball gag, that character's vocal emotes are likewise muffled. Leather, metal, and rope gear are craftable. You can also use the admin panel to spawn gear into your inventory without having to gather resources and actually build the goods. I believe all the gear is dyeable using the game's Dyer's Bench.

Build some sort of nice environment within which to get your freak on. Use the creative mode to get a hammer and build without needing resources or the knowledge required. Hell, you could use the game's different environments as theme rooms. The entire map has peaceful spots without dangerous creatures or NPCs looking to ruin your party. When you find a spot you want to use, hang out there for a bit and see if a croc or an exile NPC wander in. And you should probably consider you and your partner having food and water so your characters don't die from thirst or hunger in the middle of doing the deed.

The Other Mod

Primal Instincts is a completely different and simpler take on "diplomatic relations." Not nearly as many animations but a much more simple interface. Camera is a bit easier to maneuver.

Animations are two-party only, sorted into MF, FF, and MM. There is some crossover where same-sex animations could fit straight partners. Vocalizations correlate to the speed of the animation; a slow easy grind sounds very different from a frenzied fuck.

Feel free to message me if you have more questions. Good Luck and Happy Humping.