G04 dwell period control parameters
Basically you are fighting against oozing. So a retraction, or as you call it:


  the 3D pen I am using goes back a little bit to prevent dripping


needs to be undone. You can do this by extruding an amount to get the filament back at the tip. Command G1 Exx.xx where xx.xx is a number where the retraction is is added on top of the existing value. Furthermore, most slicing software have parameters available to influence the extrusion/retraction. E.g. "coasting" is an option to prematurely stop extruding and make use of the pressure buildup in the nozzle (this prevents blobs where perimeter end meets the perimeter begin), "extra length on restart" (replenish the nozzle chamber with extra filament) or "Retract on layer change". In principle all these actions are set and handled by the slicer you use for making a print file. There is no need for a "dwell time", in fact dwell is just a pauze. It seems a bit strange that you want to control the filament flow yourself, while all this is done for you by the slicer software.