I think the question might need reframing. The Buddha's Dhamma is of two types (MN 117):
- mundane/pertaining to merit & morality
- supramundane/transcendent
For me, the question is: "Did the Buddha ever offer supramundane teachings without being asked to?"
The account of the First Sermon in the Vinaya gives the impression the Buddha was pushy & offered to teach without being asked at a time when the five monks were not yet the Buddha's Sangha:
The Buddha said to the group of five monks, “Monks, don’t address the Buddha by name or as ‘friend’. Listen, I’m perfected and fully awakened. I have discovered the deathless. I will instruct you and teach you the Truth. When you practice as instructed, in this very life you will soon realize with your own insight the supreme goal of the spiritual life for which gentlemen rightly go forth into homelessness.
The Buddha was able to persuade the group of five monks. They then listened to the Buddha, paid careful attention, and applied their minds to understand.
In MN 49, the Buddha went to a Brahma-world to harass Baka the Brahmā, who did not attain any enlightenment from the Buddha's harassment. (However, my personal view is MN 49 is a late fake sutta).
As for mundane teachings, I expect a Buddha would provide these in the general course of meeting others socially.