Wa'alaykum assalaam sis Aishath. It is permissible to do that. However, your wudhu' is valid only within one fardh solat waqt (time). Ya'ni, if you take wudhu in zohr time, your wudhu is valid during that time. You can do nawaafil salat, etc. But when the asr time comes, you need to clean the "private part" and again do as you've done (ie block the passage to prevent the liquid from seeping out) and renew your wudhu. wallaahu a'lam. By the way, have you seen a doctor regarding your problem ? or seek any medical assistance to cure your problem ?