bathing is actually crucial to guinea pig health, specially boars because they get buildup on their scent glands by their butt. the next time i bath my pig, i'll take some pics for you, but there are tons of how to videos on youtube on how to do it.
we just use small animal (for ferrets and rabbits) shampoo or baby shampoo and put her in the sink. keep the water luke warm and get the pig soaking wet, then soap. as much as they dont like it, be sure to get their underbelly and behind areas. then you rinse (very thoroughly) towel dry, and we also blow dry. the best method for blow drying is to line a clothes basket with a towel, put the pig in, and be prepared to chase them with the dryer lol.
some pigs dont like it, some do, some learn to like it, every pig is different good luck!
good luck!
