Bill B. answered 03/01/21
Bill Art, Guitar, French, and Excel Tutor
A string cannot be percussive and sound a note at the same time. But there are more than one string on the guitar. If you watch Sungha Jung he is using his thumb on the 6 or 5 string while letting the other strings ring out. Make sure you keep your fretting hand in place in order to let the other notes ring out. You might want to practice something slow and easy in order to make sure you are slapping ONLY the 6 and 5 strings while letting the others ring. I hope that helps.