soft soap 
noun [mass noun]
1A semi-fluid soap, especially one made with potassium rather than sodium salts.Mr Mason and his brother Charles had been running a soap company in Burlington Lane manufacturing soft soap, furniture polish and metal polish, when they foresaw a good trade for boot polish and engaged a chemist to devise a formula....
- He worked down a pit, just like his father before him, and mining folk never use soft soap, either literally or figuratively.
- Slick, soft soap slipped humorously through my fingers, and my hand dove to catch it.
2 informal Persuasive flattery: he started treating us as grown-ups, telling it straight with no soft soap...
- If you look for truth, you may find comfort in the end; if you look for comfort you will not get either comfort or truth, only soft soap and wishful thinking to begin with and, in the end, despair.
- A broad smile split Ben's face, but something in Larrimore's expression made him wonder what all this soft soap was intended to prepare him for.
- This is not the brave new world we were sold, like so much soft soap, by untold motion picture, pulp novel, and television traveling salesmen.
verb
(soft-soap) [with object] informal Use flattery in order to persuade or cajole (someone) to do something: timeshare touts try to soft-soap you into buying abroad...
- Keep it curt, Kenny, and stop soft-soaping us with your loquacity and verbosity.
- They're going to allow us to continue hunting while the legal arguments go ahead, but that's just an attempt to soft-soap us so they won't have a fight when it comes to the General Election.
- LaBute probably empathizes with Byatt's 19 th-century poet Randolph Henry Ash, a tortured fool for love who is able to soft-soap intelligent women despite the ‘soft-core misogyny’ of his poetry.