Lol most piggies arent that relaxed during a bath.
I used to do baths in the sink but after them trying their best to escape I moved it to my big bath.
I put some nice warm (not TOO warm) water in the bottom, only enough to come up to their belly though.
Then I put them in together and they trot around happily and then I give them their wash down and shampoo.
I have never had a stressed out bath time with any guinea pig when bathing them in my big bath.
Obviously you have to be careful with the water temperature and not have it too deep, but they should enjoy it.
Mine arent that smelly, so theyre not bathed that often, but thats what I do when I do bath them.
xx Steph xx