When an excess accumulation of sweat and filth between one's buttcheeks enables said person to walk faster and with longer strides (or "glide" if you will). This occurs because the ass sweat reduces friction between the buttocks. Unfortunately, the benefits of being glidey are far outweighed by the drawbacks, which include: anal soreness/irritation, rashes, and localized chafing in the anal area.
One is said to be "glidey", or to have a case of "glideys".
Glideys can be caused by not wiping properly, heavy sweating, not bathing, or any number of other factors.
While walking across the parking lot in the afternoon heat, Morris immediately regretted having been so hasty in cleansing his anus after defecation. The squishiness between his buttocks, coupled with the frictionless strides he was suddenly able to take, led him to realize that he was Glidey.
At the end of the Skee-Lo video "I Wish", Skee-Lo performs a dance that appears to be possible only with the assistance of a severe case of the Glideys.