Most Improved Tapulator
You have to click Enter in the main menu multiple time, and after nothing drops, you can use the "down"-button

Go Left
Move to the left.

Go Right
Move to the right.

Early Bird
Swallow every worm.
Dont worry when you are at the end and at 8/12 worms, the credits section has the other 4 worms:
Further to, when you finished the Story you can repeat the credit part, if you press continue. That way, you can farm worms

Fire Inspector
Safely deploy all the fire extinguishers. For safety.
Actually you just have to find 23, there are actually more around the game and you can redo thE lvl and it will add to the number

Sleep No More
Don't let sleeping dongs lie.
Poke every ♥♥♥♥ which is sleeping

Paperwork
Submit your monthly physical report.
When you have to go to the office, dont go through the archive, go the reception. At the first area, where you would head to the office, there's another room with a copie machine. Copie your ♥♥♥♥ and put the paper into the paper cases.

Bulking Gear
Use all the "supplements" you can for maximal gains.
Find all Suringes at the Gym. 1 is in the Locker at the swimming pool. Some others at the box at the cardio, and the last one at the pumping station

Popcorn Buffet
Eat a disgusting amount of popcorn.
When you are at the cinema date, at all the popcorn you see

Appalling Appetite
Eat a even more popcorn

Self Defence
Use the cake knife to defend yourself from wedding guests.
Be near that knife guy who cuts the cake and steal it from him.

Clumsy
Die a lot of times in your nightmares.
Thats the level were you respawn and see your corpses

Meet Your Maker
Penetrate God
When you are on your journey around the world, leave the world to the north

Summer Job
When you have to find your luggage, fint the catcus and poke it

Swan Tamer - Story
Make peace with a gaggle of swans. Their natural instinct is to kill.
Eat the bred near the bench and spit on them
You have to chances to get it, 1 time where you walk through the park and near the end where you play as Sam.

A Better John - Story
Finish the game

Autopaedicatio - Traditional Mode
Penetrate yourself in Traditional Mode

Fussy Lover - Traditional Mode
Save yourself for that special orgy.
Don't have sex

Till Death Do Us - Date Night Mode
Have sex in the Date Night graveyard.

Safety First - Party Mode
Everyone survives having sex in a trash-compactor full of needles

Magnetic Basshole - Party Mode
Win Lights Out in under five seconds.

My Precious - Party Mode
Get all of the rings in Lord of the Rings.

The Perfect Partner - Party Mode
Marry yourself in Abstinence.

Spare Wheel - Party Mode
Be the only one locked out of an ouroborus.
So basicly the other players need to build a circle around you, and you dont have sex in the Pukaki gamemode

Generous Lover - Party Mode
Finish last in a Party Mode game.

Always Finishes First - Party Mode
Good at video games. Terrible at sex.
Win all 5 Rounds

Master Unlocker
Collect enough milk to fill the tank.
Means you have to play enough MP matches to get all rewards (takes about 12-14 games)

Couch Party
Have enough friends and/or enough controllers to play an 8 player game.
Check the controll settings

Credit to Ashelaain:
For anyone wondering: You can get Couch Party achievement by yourself using one controller and a computer with a numberpad in offline mode:

1: WASD
2: IJKL
3: computer arrows
4: numpad arrows
5: left controller stick
6: right controller stick
7: controller arrows
8: controller letters/symbols

for the achievement to pop you need to play through the rounds till the end score and it will pop.