Cool little trick for percussive sounds that i figured out
The idea is that you use your ipads/phones internal microphone, while also getting audio out of it internal speakers. Then finger drum on the ipad, use nails for snare(with two fingers so that they hit at slightly different times to create that snare type of sound) and kick with other hands soft parts of the fingers(i like to use two fingers here too, but hitting at the same time just to give it a bit more body). Then put some effects, like reverb or something and you can get pretty nice unorthodox drum sounds. This will easily create too much feedback, so try to avoid getting it to feedback too much! However a bit of feedback does make a big part of the sound, so try to get it to feedback the right amount. Also dont try to do this in a noisy environment. Also you will most likely have to trim the loop a bit as there will most likely be some random feedbacks here and there.
Heres a small example of it using ddmf envelope reverb only:
Some eq and other effects would make it sound quite a bit better, so play around with it Also try hitting different spots on ipad for slightly different sounds. I used "snare" on the lower right corner(if looked at portrait orientation) and "kick" at upper right corner on the example clip.