Hello Thanks for query. The scrotal sac differs from person to person and has no relation to conception. The problem of premature ejaculation and less libido are most of the time mind related and due to what is called as performance anxiety. Following measure will help you to boost up his confidence and getting good erection.and delay ejaculation. 1) Practice regular exercise for 45 minutes followed by meditation for 1/2 an hour in the morning. 2) Take high protein diet rich in vegetables and fruits and Vitamin A,C,D,E.and Zinc 3)Take anti oxidants like Almonds 5-6 everyday.. 4) Avoid alcohol and smoking.. He may take Sidenafil (Viagra)as on demand to have sustainable erection to have enjoyable sex. As regards conception get his semen analysis done to rule out any abnormality. Dr.Patil.