Ruby ERB render and def function

I got an strange issue with my experiments with ERB. Here what code do I have:

# cat ./services_lbs2.erb
<%= def renderVip(description, template)
puts "zxc dfg"
end
%>
# locally and remote
Printing: <%= renderVip('123','456') %>

And here what I am getting in the irb:

irb(main):034:0> @template=File.read('./services_lbs2.erb')
=> "<%= def renderVip(description, template)\nputs \"zxc dfg\"\nend\n%>\n# locally and remotely monitored (all externals)\nPrinting: <%= renderVip('123','456') %>\n"
irb(main):035:0> zxc = ERB.new(@template,nil, "-")
=> #<ERB:0x00000000068d4d88 @safe_level=nil, @src="#coding:US-ASCII\n_erbout = String.new; _erbout.concat(( def renderVip(description, template)\nputs \"zxc dfg\"\nend\n).to_s); _erbout.concat \"\\n# locally and remotely monitored (all externals)\\nPrinting: \"\n\n; _erbout.concat(( renderVip('123','456') ).to_s); _erbout.concat \"\\n\"\n; _erbout.force_encoding(__ENCODING__)", @encoding=#<Encoding:US-ASCII>, @frozen_string=nil, @filename=nil, @lineno=0>
irb(main):036:0> zxc.result(binding)
zxc dfg
=> "renderVip\n# locally and remotely monitored (all externals)\nPrinting: \n"

I could not get the output like:

# locally and remotely monitored (all externals)\nPrinting: zxc dfg\n

Why is it so and how it can be fixed?

Thanks!