Anytime you'd like. I've already started running the water, it shouldn't take too long to fill.
Any which way, really. I like firmness, roughness with it though, especially if it's followed by soothing strokes of a tongue, though that might be a bit tricky in the bath. It wouldn't be difficult for you to slip a hand between my legs, to feel how hot and wet you've made me by playing with my breasts.