Hello dear.. First of all remove all myths & misconceptions from your mind about masturbation. In fact, Masturbation is completely normal & doesn t have any bad effect to the body and mind. Regarding the problem of forgetting the studies & weakness in sexual health, it is related to the stress & lack of self confidence. So...don t worry about all this & stay relaxed Avoid stress...practice meditation..this helps in improving concentration & builds up the confidence level. Performance can be improved by having a diet rich in fruits, vegetables, fish, nuts & honey. Avoid smoking & alcohol. You can also do oil massage of the penis...it increases blood flow & maintains the erection. One more thing...avoid consuming any over the counter medication which claim to increase memory or improve performance...it may be harmful. Best thing is to eat a healthy diet, exercise regularly, avoid stress, get good sleep, think positive and stay happy. Wishing you a Healthy Life. Take care.