Last night my nine year old daughter noticed a fairly large growth (which we had never seen before) on the bottom of our dog's tail near the anus. it is soft and seems to be filled with fluid ..not sure if blood, pus or other fluid. she is not in any discomfort and the area is not hot nor oozing. since it is the weekend i am going to wait until monday (tomorrow)to contact a vet. i am thinking a possible abscess and am hoping it is nothing more serious. does any one have any idea what it could be? thank you very much.