accidentally on purpose

accidentally on purpose
accidentally-on-purpose {humorous}
(deliberately, but meant to look like an accident; deliberately, but feigning accident) — как будто случайно; как бы невзначай

If you do something accidentally on purpose, you intend to do it but you pretend that it was an accident.

Example 1: Then, I accidentally-on-purpose spilled coffee on him.— Тогда я как бы случайно пролила на него кофе.

Example 2: The wallet had been left there accidentally on purpose. — Бумажник там оставили как будто случайно.