I had some old filament waiting to print some useless, so..
I'm not expert when it goes to printing without bed heating and i had no time to learn it now, so i used bed heating for first layer with raft and rest layers bed was cold.
Ofc, supports only from build plate and be sure that support does not go in the egg.
Kinder egg is about 65x45mm, you can use another brand egg if it is similar size.
You can use gcode for color change and to pause print at ~73mm height, for inserting Kinder egg to your print. Or just do it manually.
I don't take any responsibility or liability, if you make some damage to your printer or Kinder egg!
I used with 3 perimeters, 3/3 layers.
Don't use bed heating!
You can play with settings.