by stealth

In an undetected way; silently and secretly. The cat burglar entered the office by stealth, and the only evidence he was there was the missing document. He's a huge guy, a former wrestler—I wouldn't ask him to do anything by stealth. A: "Can't you just go out by stealth after your parents have gone to bed?" B: "No, my mom somehow hears absolutely every noise in the house."

stealthing

slang The act of a male removing a condom during sexual intercourse without his partner's knowledge or consent. So-called "stealthing" is sexual assault, period.