In Jain practice, listening to the Bhaktāmbar while lying down is generally not considered proper if it is being heard with carelessness, laziness, or disrespect.

The reason is that Bhaktāmbar is a highly sacred stotra, and it should be listened to with:

• respect
• attention
• cleanliness of mind and body
• reverence

If a person is lying down only due to illness, weakness, or physical inability, and the intention is respectful, then the main focus is on bhāva (inner devotion). In that case, it is not viewed as the same as careless behavior.

So the short answer is:

• For comfort or casual listening while lying down: not appropriate
• If due to necessity, with reverence: not necessarily wrong, but still better to sit if possible

In Jain Dharma, the best practice is to hear sacred stotras sitting in a calm, respectful posture.