2007 Camry ding/metallic sound from back

[Distress]

Hello all,

Recently noticed this metallic 'ding' sound when sitting down or getting out of the car coming from back of the car. Also when slamming boot shut. A little bounce of the back of the car also produces it however sound not same all the time. Seams most loudest is when car been left for a while. Eg, park and go home return an hour later and sit down or bounce back makes most loudest on first instance after its harder to reproduce. Sound also present when bouncing car sideways a little.

Sound like a little ding sound between small metal parts (pipes?). Closest I can describe is tapping a thick glass cup with fingernail.

There has not been any traumas to the car like kerb hitting etc and the only work done recently in the back was replacement of 1 of the back tyres. Tyre is same specs as other 3. I can only hear this sound when its quieter surrounding like getting out of the car in parking. Nothing can be heard inside car while driving normally, over bumps or speed humps ever.

Any ideas what could be the cause here. Try to get some ideas before going on discovery tour with mechanic.

Thanks