Generally, a bp soaking is an indicator of something wrong. Before we can give you much advice, we need info from you about your setup.

When did you get the snake?
How old and how big is he/she?
What kind of enclosure do you have him/her in?
What kind of heat are you providing?
How are you measuring and regulating the heat?
What are your temps, hot/cool/ambient?
What is the humidity in the enclosure and how are you measuring?

Generally, some basic reasons a bp might soak are:

MITES (Most common reason for soaking in my experience)
Temperature in the tank is too hot, the snake could be trying to cool off.
Overfed - If a snake is fed too large of a meal, it may soak to relieve some of the pressure.

What I'm trying to say is that there could be a number of reasons why. It could be anything, or it could be that your snake has just decided to go for a dip. We won't be able to tell you without more info. Pics are always a plus...

ps - Welcome to bp.net. Read up, there's a wealth of knowledge at your fingertips...