JWs do not like John 6. They insist that the symbolism he uses here, "eating his flesh" and "drinking his blood," differs from that mentioned by Matthew and Paul. But in my mind, it's the same thing. In this instance he was addressing a great crowd, including Pharisees. At the end of the chapter, according to John's recollection, Jesus prophesied about Judas Iscariot, who would betray him, putting the chapter in context. In his Gospel, John did not refer to the memorial again.
Jesus said to
them, “Truly, truly, I say to you, unless you eat the flesh of the Son of Man
and drink his blood, you have no life in you. Whoever feeds on my flesh and
drinks my blood has eternal life, and I will raise him up on the last day.” Thus,
the partaking of the memorial emblems is an identifying feature of true
Christianity (cf. John 6:48-54 ESV). I think the above is bad news for those that do not partake.