Humans can generally tolerate skin contact up to 50C. Anything higher and you will pull your hand/finger away. Keeping with the "unconventional" theme, lips a

Humans can generally tolerate skin contact up to 50C. Anything higher and you will pull your hand/finger away. Keeping with the "unconventional" theme, lips are more sensitive to temperature than fingers, but make sure you don't burn your fingers before you try kissing the chip. With practice, your lips can tell which 0402 passive is getting hotter than others. Or you can buy a thermal camera.