As you mention, yes, it's probably the lubricant and your own discharge.When condoms break, it's usually very obvious. We aren't talking about little holes that you wouldn't notice; latex, when it breaks, usually tears. And if you ARE using condom-safe lubricant, it's fairly rare for rips to happen at all.
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Laurel Lemming
Scarleteen Advocate
"And when the answer that you want/Is in the question that you state/Come what may..." - Coheed and Cambria, "Blood Red Summer"