the easiest way to get round it is to preheat the machine before running a print.

After a few minutes the filament stops oozing and you can pinch it off - I use fingers, other people with non-asbestos skin could use tweezers, paper etc. I just find fingers quicker :-)

I figure I've got enough hard skin after 8 years that the tips of my index finger and thumb are now pretty much fireproof :-)

One of the features of most slicers is to print either an outline of one or two lines before starting the print or just printing a line along one edge of the bed.
basically what you did manually - most slicers will do with a few ticks anyway :-)

The reason it happens is simple.

When you heat plastic (or anything) - it expands.
The cold plastic in the hot end - heats up and the expansion dribbles out the end.

This is why a pre-heat works well.
After afew minutes there is no more cold plastic to expand and the dribble stops.

If I'm doing a number of prints I keep the printer at temp inbetween.

That and the slicers pre-extrusion does the trick.