I pump and I store my milk in the fridge. So my hubby can give it to my little one when I'm not home. At home we have a bottle warmer, but the issue is, when we are out and about in the street and my little one is hungry I try to give him breast milk from the bottle but it's cold and he spits it out, he don't want to drink it. It needs to be warm for him to drink it. Do any of you ladies have an issue with this? How did you fix it?