wiring DVC subs

The wiring should be planned before the lengths are cut.  In your case you've described one wire whose origination is point A on the first sub, has a connecting point on the second sub which would be point B, and a final destination at the amp, point C.

A wire is allowed to be left long enough to reach from point A to its final termination point at point C.  Point B is a connection too, but the wire can just be stripped of insulation at that point and the bare wire bended.  If the terminal is a binding post, that section of bare wire can be twisted around it, or if the terminal is a spade, the section of wire can be fitted with a connector.