How to Prune lily 'Mambo'?
No pruning required

lily 'Mambo' · Lilium 'Mambo'
Plant bulbs in autumn, 15cm deep, in moist but well-drained acidic soil enriched with leaf mould or well-rotted organic matter, in a sheltered position, with the base of the plant in shade, for example from ground-cover plants, and the rest of the plant in full sun or partial shade; for more advice, see growing lilies in containers
No pruning required