How do I get another pet slot xmaskarel

You get get pet slots in the MC for sP or through the pet page for CSC. The MC ones are limited (I think to 25?) and increases in price with each one you buy. I don't remember specifics on how many you can buy with CSC.

You can buy up to 65 pet slots with CSC (they're the from pet slot plushies and early totems (soft max 10) and New slot additions categories on your user dashboard)