Botmundo

High Times: Smoke a joint/bong for the first time.

High as a Kite: Smoke joints/bongs for some time.

High Maintenance: Stay high for 24 hours without the effect wearing off.

420 Superfriendly: Use a social bong while interacting with another person

Drugs are bad, mkay: Major Tom, Smelly Cat and Funky Skunk works the best. Keep using them until you see your mood is dropping. Then use more. If you see the mood isn't dropping a bit - let it wear off and repeat from the beginning.

Dude Where's My Achievement? Take 2 hits - let it wear off - take 2 hits - let it wear off - again, again, again and again until you get the achievement. Might take days, weeks. Works with any type of joints.

The Tao of Willie: Remain under the effect of the Bong (Hopalong Willie) for at least 3 hours. Use the bong once an hour until you get the achievement.