diff --git a/src/model.jl b/src/model.jl
index 4798f07d..61b4fdc0 100644
--- a/src/model.jl
+++ b/src/model.jl
@@ -146,10 +146,16 @@ struct SeqModel <: Model
   steps::Int
 end
 
-(m::SeqModel)(x::Tuple) = m.model(x)
+runseq(f, xs::Tuple...) = f(xs...)
+runseq(f, xs::AbstractArray...) = stack(f(map(x -> (unstack(x,2)...,), xs)...), 2)
+runseq(f, xs::BatchSeq...) = rebatchseq(runseq(f, rawbatch.(xs)...))
 
-splitseq(xs) = unstack(rawbatch(xs), 2)
-joinseq(xs) = rebatchseq(stack(xs, 2))
+function (m::SeqModel)(x)
+  runseq(x) do x
+    @assert length(x) == m.steps "Expected seq length $(m.steps), got $(size(x, 2))"
+    m.model(x)
+  end
+end
 
 (m::SeqModel)(x::AbstractArray) = stack(m((unstack(x, 2)...,)), 2)
 (m::SeqModel)(x::BatchSeq) = rebatchseq(m(rawbatch(x)))