taxability of honorarium

My cousin's uncle seems to have trouble deciding under which head to pay tax on honorarium that he frequently receives for lectures he gives. He receives it from multiple sources and on some of those receipts TDS has been deducted at the rate applicable to prof.fees.
So should his uncle disclose the honorarium income as Income From Other Sources or as Professional Income(if prof.income, can he make use of section 44ADA for presumptive taxation)?
urgent reply needed.