You got it. One more thing, try to hit the string with a very small surface area on the side of your thumb. The less of your finger you get on the string, the less likely you are to get tangled up on the D and E strings or cause them to ring out.
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Nearsighted monitor engineer: "What the hell is an Anemic F-1X?'"
It's gonna take a lot more than 2 months to play slap bass well!
Slowly work on your aim on EVERY string. Looking for clean solid notes.
I would slap the low G on the E string an plant my pinky on the C on the G string and pop that. Then play the C on the A and pop that same high C... then slap the F on the D and pop the C, then the Bb on the G string and pop the C. Like this:
SP SPSP S P SPSPSP
__5_5_5_3_5_5_5_5____
_____3_____3_________
___3_________3_______
_3_____________3_____
That way you can practice each string. Do the opposite too. Plant the slapped note on the low G and move the popped note down.
Where is your hand when you are playing, it its perched above the E or is your whole wrist below the strings, I found that i soon as i dropped my wrist i was able to become more accurate and as stated before get a smaller surface area of my thumb onto the string to avoid hitting the D or E.
i prefer to slap with my thumb parallel to the strings and my wrist straight and the wrest of my hand perpendicular to the strings. the only thing that should be moving is the rotation of your wrist. you also want to pull your thumb away immediately, otherwise itll get muted and muddy. just slap octaves for a really long time. its fun!
I've recently been dink'n around with slapping too, and I don't seem to be able to get a clean A string note either without muting the E & D simultaneously.
Slapping the A string? 
