hello user. if your Erect penis size is 4.5 inches - you need not worry much over this issue , as persons even with 3 inches penis length reported having adequate sexual pleasure as it is enough for stimulation of clitoris (female erotic zone) and insemination of sperms - anyways sexual performance depends majorly on other factors like your level of attraction towards partner, quality of foreplay etc - there are surgical procedures and devices for the purpose but they are not satisfactory for majority of persons and bear there own side effects . so "relax" and have a happy married life :) - hope i answered your query - if satisfied please rate the answer