Some great tips here, especially about making sure you're wearing - or rather not wearing - the correct underwear

There's also various types of chamois cream. Some are good for stopping rubbing, while others are anti - bac and anti- fungal which can be useful if you're in your shorts all day every day or think you might be susceptible to candida infection.

I've got some stuff that's like petrolum jelly which is also anti - bac and I use it every time I ride, except for the shortest of distances. Helps keep the rubbing or chaffing away.