It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that he said: "When one of you performs ablution, let him take a handful of water and sprinkle it on (the area of) his private parts. Then if he feels any trace (of wetness after ablution), let him say: 'Inna dhalika minhu' (Indeed, this is from that (water which I sprinkled))."
Imam Musaddad narrated this report (athar) in his Musnad, and its chain is sahih (authentic).
Hadith Referenceالمطالب العالية بزوائد المسانيد الثمانية / كتاب الطهارة / 114
Hadith Gradingمحدثین:إسناده صحيح، موقوف
Hadith Takhrij«حکم الحدیث المطالب العالیہ محققاً تنسیق د. سعد بن ناصر بن عبد العزيز الشَّثري- مکتبہ شاملہ :موقوف، إسناده صحيح. » «أخرجه البيهقي فى«سننه الكبير» برقم: 774، وأورده ابن حجر فى "المطالب العالية"، 114»