diff --git a/requests_mock/mocker.py b/requests_mock/mocker.py
index b9e5f5e..095230d 100644
--- a/requests_mock/mocker.py
+++ b/requests_mock/mocker.py
@@ -10,7 +10,9 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import contextlib
 import functools
+import sys
 import threading
 import types
 
@@ -36,6 +38,22 @@
 _send_lock = threading.RLock()
 
 
+@contextlib.contextmanager
+def threading_rlock(timeout):
+    kwargs = {}
+    if sys.version_info.major >= 3:
+        # python2 doesn't support the timeout argument
+        kwargs['timeout'] = timeout
+
+    if not _send_lock.acquire(**kwargs):
+        raise Exception("Could not acquire threading lock - possible deadlock scenario")
+
+    try:
+        yield
+    finally:
+        _send_lock.release()
+
+
 def _is_bound_method(method):
     """
     bound_method 's self is a obj
@@ -137,10 +155,7 @@ def _fake_send(session, request, **kwargs):
             # are multiple threads running - one thread could restore the
             # original get_adapter() just as a second thread is about to
             # execute _original_send() below
-            if not _send_lock.acquire(timeout=10):
-                raise Exception("Could not acquire threading lock - possible deadlock scenario")
-
-            try:
+            with threading_rlock(timeout=10):
                 # mock get_adapter
                 #
                 # NOTE(phodge): requests.Session.send() is actually
@@ -175,8 +190,6 @@ def _fake_send(session, request, **kwargs):
                 finally:
                     # restore get_adapter
                     _set_method(session, "get_adapter", self._last_get_adapter)
-            finally:
-                _send_lock.release()
 
             # if we are here it means we must run the real http request
             # Or, with nested mocks, to the parent mock, that is why we use