Hello Masterbation  usually doesn't effect sperm quality. You can get sperm analysis test done , to know about the sperm count and quality. In this test Semen (by Masterbation) needs to given in special container provided by the laboratory. You need to avoid mastubation for 24 to 48 hrs before giving the sample for the test . Test report will tell about sperm count, speed, structure and other details. Depending on report it can be decided if you have normal parameters or you need any treatment .