This obscure lyric has been variously interpreted, though "Colinet" is certainly Spenser and "Amyntas" Thomas Watson; "A-mint-Asse" might be Watson's translator, Abraham France, and "Hobby-Horse" Gabriel Harvey ("Hobbinol"). "R. B." is generally identified as the Spenserian poet Richard Barnfield.
George Klawitter: "Stanzas 3 and 4 are addressed to Watson, dead shortly before Greene, and beg Watson to come forward and teach Greene to 'Leave the game as hee began,' presumably more gently than Greene had lived" Complete Poems (1990) 197n.
Klawitter also sees references to Spenser in Sonnet V and VIII: "Barnfield admired Spenser, was the first to imitate the Spenserian stanza, and borrowed entire lines from him. Since Spenser was probably aligned in Barnfield's mind with the hated Harvey, these lines in Sonnet V may very well express the tense ambivalence with which Barnfield viewed Spenser at the time. Torn between respect and anger he might very well be attempting in these lines to bring Spenser around from the anti-Greene faction (whether Spenser was in it or not) into the pro-Greene faction" Complete Poems (1990) 198n.
The identity of "R. B." is not certain, however.
Come from the Muses well Minerva,
Come and bring a Coronet:
To crowne his head, that doth deserve,
A greater gift than Colinet.
Come from Bacchus bowre Silenus,
Come and bring some good-ale grout:
For to sprinkle Vino-plenus:
All his foolish face about.
Come thou hither sweet Amyntas
All on a silver sounding Swanne:
Come and teach this fond A-mint-Asse,
Leave the game as he began.
Come thou hither my friend so pretty,
All riding on a Hobby-Horse:
Either make thy selfe more witty:
Or againe renew thy force:
Come and decke his browes with baies,
That deserves immortall praise.