According to Osho, respect is measured by the heart behind the question, not its tone. Playful or naughty questions can express deep love and trust; then everything is allowed and even becomes holy. Without inner trust, even solemn, ‘respectful’ queries are mere formality and, in fact, disrespect. Before asking, look within: if your inquiry springs from trust, ask anything.
It’s not whether your question is a joke or serious; what matters is that it comes from love and trust in your master.