calentito
warm
caliente
hot
+
-ito
diminutive suffix
Calentito means warm and can be thought of as caliente0 (hot0) with the diminutive suffix -ito1, making it a little hot1, or warm.
adjective
- warmWarm or hot, usually referring to food or drinkMe gusta tomar el café calentito por la mañana. // I like to drink hot coffee in the morning.