This sound effect can be found on Cartoon Trax Volume 1, which was made by The Hollywood Edge. A higher pitched version of this sound, SQUISH, CARTOON - LITTLE SQUISH, can be found on the Hanna-Barbera Sound Effects Library. Links: https://soundeffects.fandom.com/wiki/Hollywoodedge,_Wet_Splats_Various_CRT052303#Audio_Samples