Don't speak of your bhajan here and there - Apana bhajana katha ... Narottama Das Thakur

Sri Ananta Das Babaji Maharaja's commentary: Now Srila Thakura Mahasaya concludes this Prema Bhakti Candrika by explaining how a devotee conceals his realisations in bhajana. The light of the moon of loving devotion must always be kept hidden within the heart, and by doing so the heart will be illuminated and cooled off, and the Cakora-bird-like life-airs will be blessed with the relish of the sweet nectar of prema. The devotee should take care that he does not reveal his realisations in bhajana to every Tom, Dick and Harry.

When it is necessary the practitioner will reveal them to Sri Gurudeva and his own intimate rasika devotee-friends, but never to anyone else. It would harm his humility and would inevitably damage his bhajana. Prior to this Srila Thakura Mahasaya has repeatedly warned the practitioners about this in verses like: rAkho prema hRdaye bhariyA ("Keep your love hidden in your heart"), and gupate sAdhibe siddhi ("By secretly practising you attain perfection"). We can understand how important this point is because it is repeatedly mentioned.

Srimad Jiva Gosvamipada has written in the end of his Bhakti Sandarbha (339)—



"Whatever confidential experiences are attained in connection with the practice and the goal given by the grace of Sri Guru or Sri Bhagavan, and that are one's very own treasure, should not be revealed to anyone. In Srimad Bhagavata Sri Vishnu tells Sri Aditi-devi—'O devi! Whatever secrets I told you, should never be revealed to anyone, even if someone inquires after it! All secrets of the gods in the sky will yield fruit only when kept secret."

Veda guhya katha ei ayogya kohite (C.C.) — "It is improper to speak about these matters that are secret even to the Vedas!"

Nice! It sounds to me like if it is an “bhajan-aparadha" (to reveal to the outsiders one's inner bhajan) And it sounds a bit trantric, too:

There is another sanskrt sutra on that theme which I came accross in a foot note of the Gita Press Bhagavat in the 11th skandha somewhere saying to the effect, a virtue spoken is a virtue lost. I will try to find the original. The idea being that one should not glorify oneself by boasting, however covertly, and if one does he loses what it was he may have gained. That's why it is best to make the the verses of the Goswamis our realisations and then just quote them. rupa raghunAtha pade haibe Akuti/kabe hAma bujhAba se yugala pirIti// When will I become so eager for the poetry of Rupa and Raghunatha? and when will I thereby comprehend the love of the couple?

Utterly unworthy as a blade of grass,
Forebearant like the patient tree;
Prideless, still giving honour, thus,
One may ever sing the praise of Hari.