Yep, all good, it's a nice poo.
Rubbing their nose on the glass is behaviour you might see anyway, it's just them trying to get through or maybe responding to reflection. Keep an eye on it, my BTS was really naughty in our summer climbing up the glass incessantly. If yours keeps rubbing or starts climbing you might have to do something to try and get him/her to stop. No need to panic, just FYI.
