Sounding
Sounding is the act of inserting something, usually a sound, into the urethra. It is done for immediate stimulation, and also as a means of stretching the urethra. If done frequently, the urethra will, over time, stretch so that its natural size is quite large.
While sounding tends to be a male pursuit, many women also enjoy urethral stimulation, although shorter objects must be used as the female urethra is substantially shorter. Some women practice sounding prior to getting a Princess Albertina piercing to get the urethra used to stimulation.
Tips
When being used, sounds should be lubricated using KY. Some beginnners choose to use a little Xylocaine Jelly the first few times. Keys to comfortable insertion include not using force to insert (gravity should be enough), and a relaxed state help greatly.
Objects to be inserted into the urethra should ideally be sterile, or at the very least washed well with antimicrobial soap. The introduction of bacteria into the urethra can lead to urinary tract infection.