I stand on the roof but never take a leap. I swallow black clouds, yet I do not eat. In winter I breathe, in summer I sleep. What am I?

A canvas carrier, secrets to hold, Filled with whispers, tales yet untold. Journey afar, fate in its fold, Through rain or shine, stories unfold.

In the lab, I stand, slender and glassy, a vessel for concoctions, both wild and classy. A scientist's trusty sidekick, holding secrets without a leak.

I can go on arms or be of them. I’m on cars and walls but not above them. I can be a blanket of material lest I am a family crest

Ring this when you visit someone, But careful: don’t do it more than twice. Patience is key when you haven’t got one.