Hi. First of all : get one thing clear- masturbation is absolutely healthy and physiological process, so no guilt is necessary. You can have a masturbation 2 to 4 times in a week and this is absolutely normal. Secondly : The left testis is usually lower than the left. In your case this is enhanced ( more) as the probable cause can be development of varicocele ( again more common on left side). The development of varicocele cases the scrotal skin to sag more to lower the temperature of the testis as a natural process. . Now the cord gets long enough along with laxity of the supporting muscles not allowing it to be pulled up. I would advise you to get an opinion of a Urologist to get the clinical picture clear and confirm the diagnosis and to now the degree of the disease to decide the course of treatment. In grade 3 varicocele request your Doctor to undergo the semen analysis done as a routine test and to undergo surgery in the scrotum to reduce the mass of varicocele. Till then use lungot / scrotal support. Bathe the scrotum at least twice with normal or cold water to make the area clean and elevated.