1) Gemini's not at all human, although to the eye Garett wouldn't be able to tell that. If she knows he has incredible hearing she might go to the trouble of creating the sound of rushing blood and faking a heartbeat, but most of the time she just can't be bothered. So that's a clear clue, but the most obvious thing would be that she smells like rubber, not strongly, but it's there, and she really doesn't smell of anything else human.
2) Most of the time perfume and soap/shampoo which she wears to cover the rubber scent, but he might be able to pick up on grease from the air ducts she regularly slithers through, or possibly some blood from best not to ask where.
3) She's usually pristine in her own form to a degree that's not humanly possible. Why be a shapeshifter and not make yourself look perfect? Otherwise her clothes are a part of her, so no fabricy smells either >.>
4) She has an American accent, but can mimic virtually any other perfectly once she's heard enough of it. Also she speaks fluent French.
5) Yessss (mun is squeeing)...but she's likely to snap out of it quickly.
Gemini
2) Most of the time perfume and soap/shampoo which she wears to cover the rubber scent, but he might be able to pick up on grease from the air ducts she regularly slithers through, or possibly some blood from best not to ask where.
3) She's usually pristine in her own form to a degree that's not humanly possible. Why be a shapeshifter and not make yourself look perfect? Otherwise her clothes are a part of her, so no fabricy smells either >.>
4) She has an American accent, but can mimic virtually any other perfectly once she's heard enough of it. Also she speaks fluent French.
5) Yessss (mun is squeeing)...but she's likely to snap out of it quickly.