If you do not make silicone mold very often, there is definitely something else you can use.
One of the most common releasing agent would be Vaseline oil. It should work fine on liquid silicone, but it's not a good choice for silicone gel/paste. Trust me:-)
Silicone liquid VS. paste (gel)
1. the silicone paste is much cheaper than the two part liquid.
2. the silicone paste cured much faster, like 10-15 mins, while liquid usually take about 8 hours
3. the liquid is more user-friendly, you can make perfect mold without lots of efforts; the paste requires more skills.
My releasing agent: Elmer's Carpenter's Wood glue
apply a thin layer of the glue to the area you want with finger, it will dry in a minute to form a thin film.
Since silicone won't stick to most things firmly, you can easily peel off the glue film later.
Here is what it looks like:
Apply a thin layer of glue
The glue can be easily peeled off