Mus'ab bin Sa'd narrates from the umm walad (slave mother of his child) of Sayyiduna Sa'd (may Allah be pleased with him) that Sayyiduna Sa'd (may Allah be pleased with him) used to practise 'azl with her.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 14316