1) Usually I get worried about getting aroused,
and sometimes after slight arousal, minute amount of mazi
accumulates just within the cavity of the tip of the private part, which is
visible, so where does it cross so wudhu is regarded
بِسْمِ اللهِ الرَّحْمنِ الرَّحِيْم
In the Name of Allah, the Most Gracious, the Most Merciful.
1) The wudu will break as soon as mazi is visible on the tip of the private part, even if it is within the confines of the cavity. (Shami: 1/285, Ma’rifa; Tahtaawi: pg 86)
2) If you are certain or you believe most probably that the wetness is mazi, it will be counted as mazi. Otherwise, it will be considered water.
3) If the tissue absorbs wetness (i.e. urine or mazi etc.) from the urethra, the wudu will break.
4) If your pour sufficient water (i.e. at least 3 times the amount of water needed to cover the pimple area) over the pimple area, then the water will be pure and, hence, your body will not become impure. (Shami: 1/333, Saeed)
And Allah Ta'ala knows best
Mufti Faizal Riza