I’ve been singing “Sunshine Of Your Love” all my life, and in so doing I manage a decent Jack Bruce impersonation. I’ve been singing it with friends, in the car and in the shower for decades, and when I come to the fourth line I’ve always sung “give you my dog’s surprise.”
A dog being surprised by anything is a superfluous notion (dogs live in a constant state of surprise and stimulation) and certainly inconsequential in the light of any kind of cosmic perspective, but I can’t change now — gotta be “dog’s surprise” until my dying day.