[ufobydeath]

I've been in this situation before (actually, on both sides as I have very flexible limbs) and I usually stop cranking for a second and ask if they are ok. If it turns out I'm not getting them with the armbar I usually improvise; if I'm getting the armbar from the bottom I twist and sit up in an omoplataish position and go for a facelock or a choke (and no flexibility will save you there) and if I'm getting it from mount I'll lock on a short arm scissor (you might be flexible but getting your bicep crushed still hurts like a bitch).

In short: go for chokes and compression locks.