1
Where are you going for your honeymoon?
To sign this, ask 'HONEYMOON YOU GO WHERE?' Start with the sign for honeymoon, point to the person, sign 'go', and finish with 'where'. Remember to furrow your eyebrows at the end, which is the grammatical marker for 'wh-' questions in ASL.
2
We went to Hawaii for our honeymoon.
You can express this by signing 'OUR HONEYMOON HAWAII'. First, sign 'our' by sweeping a cupped hand from your dominant shoulder to your non-dominant shoulder. Then, sign honeymoon, and finish with the sign for Hawaii, tracing a circle around your face.
3
They are on their honeymoon right now.
To sign this sentence, point to the couple (or the space where you established them), sign 'HONEYMOON', and then sign 'NOW' by dropping both 'Y' handshapes down in front of you. This clearly indicates that their trip is currently happening.