A circumcision is called "low" when more mucosa tissue and less shaft skin is removed.

This places the scar closer to the glans penis. Compared to a high cut, this has the disadvantage of removing more of the frenulum and the sensitive mucosa tissue.

In a very low circumcision, nearly all of the mucosa (inner foreskin) is removed, leaving a scar at the sulcus.  This gives the penis a smoother appearance, but it removes all of the frenulum. A low circumcision must be performed freehand and requires skill to properly skin the mucosa back, cut it away, bring the shaft skin forward and align them.  The terms "high" and "low" are not related to the terms "loose" and "tight".

Image Source: www.circlist.com