try the following

Sub CopySelection()
If Selection.Rows.Count < Rows.Count - Range("B" &
Rows.Count).End(xlUp).Row Then
Selection.Copy
Range("B" & Rows.Count).End(xlUp).PasteSpecial
Else
MsgBox "Cannot paste selection - not enough rows"
End If
End Sub

very easy to change this to an addin to you can have it as a button on
toolbar for all spreadsheets - let me know if u need this.