Hit moar notes

Oh right, this isn't guitar hero 0_0

Its a hard technique to explain to someone without a video. Basically you put your hand in a thumbs up sign, loosen up immensely, and then whip your thumb down onto the string, and take it off fast. To pop, hook under the string and pull it up, then let it snap back on the fretboard. I'm sure someone can explain it better than I can.

Applehead does a great job of trying to explain in words what slap is and how to do it.

I've just recently been able to get some semblence of slap technique down. Octave slapping is fairly easy and a good way to practice your slap and pop and get the technique and some speed.

Also check out Larry Graham's instructional videos on YouTube. Like IndianRockStar says above, a picture (or video) is worth a thousand words.
treat your bass like a drum when you: thump-whip your thumb right next to your highest fret+pop:pull your string out and let go once you're off the fretboard height alittle less than an inch.

and watch people give instructions on youtube.
Quote by FatalGear41
I wouldn't call what we have here on the Bass Forum a mentality. It's more like the sharing part of an AA meeting.

Quote by Jason Jillard

Warwick Fortress>>Acoustic AB50

slap: hit the string with the joint in your thumb, and make sure to keep it parallel to the string, also make sure you're not muting the note.

pop: put your index finger underneath the string and then pull your finger away from the string, which will make it slam against the frets and give you that poppy sound.

a few words of advice, DO NOT look at Flea to learn this technique. He tends to hold his thumb perpendicular to the string, which is very limiting if you ever want to attempt double thumbing.