Devanagari keyboard in iOS8.x

Does anyone know how to get the avagraha on the the iOS8.x keyboards or a third-party keyboard app that has this character? I'm not sure the iOS keyboards have ever had these. It's those S-shaped characters that usually make a show at the end of screams and cries in comics, like:

Also has a grammatical role in marking vowels omitted in sandhi, but I thought this might ring a bell 🙂