I'm 152cm n 42kg. I bulk up very fast wen I play tennis compared to my friends. Within 3 sessions, my arms become defined. Is there anyway 2 slow down?

No. The amount of muscle, and the shape and definition of the muscle, that one gets with a particular work-out activity is determined by genetics (which influences the levels of hormones and muscle regulating chemicals in the body). There is no healthy way to avoid getting nice muscles from sports, and it's a good thing to have as one gets older and muscles start to age.