It is highly advisable that one should keep a towel under the baby seat. The reason being baby spit and throws food particles and liquids, and these can accumulate under the seat of a baby. As a result, there is a high chance of stain on the upholstery.
You can also place a sheet of any heavy plastic along with an absorbent towel under the seat in order to prevent the damage both from food particles and liquids. And then secure the seats as per the instructions provided by the manufacturer.

Related posts brought to you by Yet Another Related Posts Plugin.