Not at all. We strive to use language that is inclusive, respectful, and positive. This phrase fails on all those fronts. It is offensive and not suitable for public or private conversations where decency is expected.
This is a rather inappropriate and unclear statement. 'Cum' is a vulgar term. It could potentially be a very offensive or misphrased expression that doesn't have a proper 'good' meaning in a general sense.
Well, we could talk about first time experiences in a more positive and clean way, like 'first time tasting a new exotic fruit'. It was really exciting. I remember the first time I tried a dragon fruit. Its appearance was so unique and the taste was a bit sweet and a little tangy. It was a whole new sensory experience.
Sharing such explicit experiences is not appropriate in most social and public settings. It involves very private and often sexual content that violates social norms of propriety and respect for others.