The scrotum is genitals out of the man of one the part be a penis under of bag form thing, the touch contains sex pleasant sensation, the child is period for the skin color, become adult a color to get dark, and living a grain form hair bag, grow sparse pubic hair. Layer outside the scrotum is a thin skin, Inside the layer is a smooth muscle, the scrotum can stretch to protect testicle with constringency thus with the environment dissimilarity and sex excitement, when outside temperature is lower, scrotum constringency, the testicle is press to close to belly, in order to prevent freeze bad testicle, the eyes see scrotum at this time, two testicles not obvious, scrotum for tightly stick under the stomach of hemisphere form, when outside temperature is higher, for spread hot, at this time scrotum flabby unfold, the bottom of the testicle hang, the eyes see scrotum at this time, two testicles very obvious, by hand touch, very easily touch the testicle in the scrotum, and can also touch vice- Gao, vas deferens, sex excitement, scrotum would also constringency, bring up testicle, make the testicle is in the process of have sexual intercourse in don't need be subjected to squeeze.