Hello Thanks for query. You have retrograde Ejaculation. You have undergone RIRS ( Endoscopic surgery )for Kidney Stone and Stent was placed in your renal unit to help to pass the the fragments of the stone without pain. Normally we prescribe Tomsulosin after removing the stent for couple of days which acts as a smooth muscle relaxant and helps to pass out residual fragments without pain The Tomsulosin keeps bladder neck wide open which during ejaculation causes passing of the semen into bladder instead of passing out in urethra This is called as Retrograde Ejaculation. Do not worry thiswill get resolved once you stop taking Tomsulosin. Dr.Patil.