"Warmmer" places added emmphasis on the warmmth and awesommeness of an object by doubling the letter m. Doubling of the letter m in any word injects it with a secret "mm" as in "mm mm mm good". Something that makes you warmmer, thus, not only increases your heat but gives you that extra special kind of heat...the kind that makes you go "mmmmmmm"
"Baby, your insides are way warmmer than your mama's."
"Damn! This cat on my lap makes me warmmer!"