What context are you talking about? BJJ competition? MMA competition? Self defense? There will be different tactics for each. TBH, if all he has done is pin your arms (using both of his, I assume), you really aren't in that much danger - assuming one-on-one combat. He has to let go of one of your arms to do something, and that can give you the opportunity to respond.
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"In case you ever wondered what it's like to be knocked out, it's like waking up from a nightmare only to discover it wasn't a dream." -Forrest Griffin