I don't totally understand your question.
If a sequence is playing you cannot record anything extra without first stopping it & pressing the record button. However, you can then leave it looping with the OVER DUB button lit up in which case any pad you play will get added to the recording.
If you don't want to add you loop with the MPC's pads you can use a midi keyboard. The other way to record things without the pads is using copy & paste in STEP EDIT mode, but that is slower & you cannot have things playing.
The other thing you might be talking about is when you have sequence with different pads triggering different samples all on different tracks of the sequence. You then "play" the mix by switching tracks on & off, but again the best way to do this is with the pads.
Did you mean something else????
