1. To speak charmingly or flatteringly to or about one, especially so as to persuade one of something or to do something. The ambassador has been putting some sweet lines on the other country's military regime, aiming to reach some compromises and ease tensions in the region. The political outlet laid some sweet lines on the presidential hopeful in its endorsement of his campaign.

2. To say sweetly amorous things to one. We stayed up all night, with Tom putting some sweet lines on me as we watched the sun come up over the horizon.